United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued September 16, 2009 Decided November 20, 2009

No. 08-7083

SARAH CARR, ET AL.,

APPELLEES

v.

DISTRICT OF COLUMBIA,

APPELLANT

Appeal from the United States District Court

for the District of Columbia

(No. 1:06-cv-00098-ESH)

Stacy Anderson, Assistant Attorney General, Office of the

Attorney General for the District of Columbia, argued the cause

for appellant. With her on the briefs were Peter J. Nickles,

Attorney General, Todd S. Kim, Solicitor General, and Donna

M. Murasky, Deputy Solicitor General.

Daniel M. Schember argued the cause for appellees. With

him on the brief were Susan B. Dunham, Arthur B. Spitzer, and

Fritz Mulhauser.

Before: SENTELLE, Chief Judge, GRIFFITH, Circuit Judge,

and SILBERMAN, Senior Circuit Judge.
2

Opinion for the Court filed by Senior Circuit Judge

SILBERMAN.

Opinion concurring in part and dissenting in part filed by

Chief Judge SENTELLE. 

Opinion concurring in part and concurring in the judgment

filed by Circuit Judge GRIFFITH.

SILBERMAN, Senior Circuit Judge: The District of Columbia

appeals the district court’s grant of summary judgment in favor

of a class of plaintiffs. They participated in a protest march

through the streets of Washington D.C. and were arrested by

District police after the protest became violent. The plaintiffs

sued, alleging they were arrested in violation of their First and

Fourth Amendment rights. The district court granted them

summary judgment on Fourth Amendment grounds, but the only

relief provided was an injunction ordering that plaintiffs’ arrest

records be expunged. We reverse and remand for further

proceedings.

I

On the evening of President George W. Bush’s second

inauguration, January 20, 2005, a group of several hundred

people, including four of the five named plaintiffs in this case,

gathered at a church at 1459 Columbia Road N.W., in

Washington, D.C., for an “Anti-Inaugural Concert.” The

Metropolitan Police Department was aware of the event through

routine Internet monitoring and assigned an undercover officer

to attend. He was directed to report any potentially illegal

activity or public safety concerns through a chain of command
3

1

 Of course we take the facts and all reasonable inferences

therefrom in the light most favorable to appellant, the nonmoving

party. See e.g., Currier v. Radio Free Europe/Radio Liberty, Inc., 159

F.3d 1363, 1364 n. 1 (D.C. Cir. 1998).

that ended with Special Operations Division Commander, Cathy

Lanier.1

While at the concert, the undercover officer saw a flier

promoting a march to protest the inauguration of President Bush.

The march was to start immediately after the concert. It came

as a surprise to the police department: it was not publicized on

the Internet and the demonstrators had not obtained a permit for

the march, as required by District law. The flier advertised that

the march would begin at the church and proceed through the

Columbia Heights neighborhood to the Washington Hilton at

1919 Connecticut Avenue N.W., where one of the inaugural

balls was taking place. And the flier stated the march was to be

an “explosive protest.” The undercover officer heard someone

announce from the stage that the protestors planned to “crash”

the inaugural ball and also heard some protestors talk about

damaging property along the route. He also reported that at the

conclusion of the concert, organizers distributed bandanas and

vinegar. Detective Drew Smith, the officer to whom the

undercover officer reported, stated that vinegar is often applied

to bandanas in such contexts to create a makeshift “gas mask,”

which mitigates the effect of pepper spray or tear gas. 

As the concert concluded just after 11:00 p.m.,

approximately 500 people left the church. Smith was waiting

outside in an unmarked car. He observed some concert goers

leave the area. A large group, however, including four of the

five named plaintiffs, congregated at the intersection of

Columbia Road and 16th Street N.W. Many in the group lit

torches – large poles supporting soup cans with flaming liquid.
4

A number of others covered their faces with bandanas.

Eventually, about 250 to 300 people began marching westbound

on Columbia Road. As they marched, carrying the torches, they

pounded on plastic buckets and chanted loudly. Detective Smith

and other officers in marked police cars followed behind.

All of this information as well as the undercover officer’s

belief that protestors would engage in violence was conveyed up

the chain of command to Commander Lanier. She decided to

monitor the events in person. She arrived at the scene in a

department cruiser just as the group crossed the intersection of

Columbia Road and 16th Street N.W. Commander Lanier was

accompanied by Officer Patrick Keller who served as her

“scribe.” Their cruiser turned onto Columbia Road and

followed the marchers from behind. 

As the march progressed, various officers on the scene

witnessed acts of vandalism. Smith observed protestors

dragging newspaper vending machines into the street to prevent

police from following behind them. Others used their bicycles

to block traffic at intersections. Commander Lanier saw a

number of marchers use their flaming torches to set fire to debris

in trash containers along the street and the undercover officer

witnessed marchers spray painting buildings and cars.

As the march reached the 1700 block of Columbia Road

N.W., it became even more destructive. The demonstrators

broke windows or glass doors at several different businesses on

that block. The undercover officer reported to Detective Smith

that he observed “persons within the march” propel missiles

with “wrist rocket slingshots” to break some of the windows.

Each time a window was broken, according to Keller, the group

cheered and its members raised their arms. It appeared to him

as though the entire group was celebrating the destruction of

property. Commander Lanier also viewed the celebrations as a
5

group response, as opposed to the actions of just a few

individuals. When the marchers reached the Sun Trust Bank at

1800 Columbia Road N.W., members broke several of the

bank’s windows. Once again, Keller witnessed the group

cheering with members raising their arms in response to the

destruction. At about this time, the fifth named plaintiff –

Matthew Singer – ran out of the nightclub he was in to join the

march. Ominously, someone in the group threw a rock or brick

through the window of the police department’s Latino Liaison

Unit office followed by more loud cheering and waving by what

appeared to Officer Keller as everyone in the group. 

Commander Lanier, in response to the destruction, ordered

two of the department’s Civil Disturbance Unit platoons to the

area. According to the officers’ affidavits, one such platoon

arrived from the south and set up a police line across 18th Street

north of Belmont Road N.W. in front of the oncoming

demonstrators. The other platoon arrived from the north and

traveled south on 18th Street, coming behind the demonstrators.

This latter platoon included a marked police car driven by

Lieutenant Jimmie Riley and several police department vans.

As Riley’s car arrived directly behind the marchers, one of the

protestors hurled a brick into the windshield of the police

cruiser, shattering it. After that, numerous other demonstrators

threw objects including rocks and bottles at the police car and

police vans. 

Based on all of the above described events, Commander

Lanier ordered that the protestors be arrested. But as officers

from Lieutenant Riley’s platoon emerged from their vehicles,

many of the protestors ran away – south along 18th Street.

Stopped by the police line formed across 18th Street, this group

of protestors turned into an alley running from 18th Street to

Columbia Road. Once in the alley, the marchers’ escape was

prevented as another police line blocked the other exit from the
6

alley to Columbia Road. Lieutenant Riley and members of his

platoon followed the group into the alley and arrested them

there. No order to disperse was given prior to the protestors’

arrests. In all, 65-75 people, including all five of the named

plaintiffs in this case, were arrested in the alley. Though

Commander Lanier believed she had probable cause to arrest the

protestors for rioting, she directed that the field arrest forms

indicate that the arrest was for parading without a permit.

Charging the protestors with the lesser charge of parading

without a permit allowed the arrestees to take advantage of

expedited release procedures that would not apply to rioting

charges.

The named plaintiffs do not dispute that they marched in the

protest. Four of the five – Sarah Carr, Allyson Kirk, Chelsea

Kirk, and Jonathan Scolnik – attended the concert and marched

with the group from the church to the area where property was

destroyed. The other named plaintiff, Matthew Singer, was in

a bar near 18th Street and Columbia Road N.W. when he saw

the protestors march by; he admits that he then ran out to join

the group. Nor do plaintiffs dispute that some persons near or

among the marchers engaged in acts of property destruction.

They do, however, challenge the police officers’

characterization of the group’s response. While the police

affidavits suggest the entire crowd appeared to be encouraging

the property destruction, several of the plaintiffs suggest that

they were not even aware of any vandalism, let alone that they

or the entire group cheered in support of it. 

The named plaintiffs also dispute how they came to be

arrested in the alley. All of them assert that they marched past

the 18th Street entrance to the alley, turned right on Belmont

Road, and turned right again back onto Columbia Road. Carr,

Scolnik, and Singer claim that police then herded them into the

alley via the Columbia Road entrance where they were arrested.
7

Chelsea and Allyson Kirk assert that they entered the alley from

Columbia Road voluntarily because it was the shortest way to

return to the Metro but that they were arrested by police once

they walked in the alley.

The plaintiffs brought a class action suit against the District

under 42 U.S.C. § 1983, alleging that all those who were

arrested and who “committed no other act providing probable

cause” were arrested in violation of their First and Fourth

Amendment rights. After discovery, the parties filed crossmotions for partial summary judgment on the issue of liability.

The district court denied the District’s motion for summary

judgment and granted summary judgment in behalf of the

plaintiffs. 

Plaintiffs’ arrests violated the Fourth Amendment,

according to the district court, because the police, as a matter of

law, simply could not have had probable cause to arrest those in

the alley. Even viewing the facts in the light most favorable to

the district, the police did not have justification to arrest on any

of the proffered bases. That was so because the statement of an

officer that the mob acted uniformly in celebrating the

destructive acts of individual protestors was only a “generalized

statement” insufficient as a matter of law to establish probable

cause vis-a-vis the class. The court’s key holding was that it

was fatal to the district’s position that the officer lacked

“particularized grounds” to believe that every one of the seventy

persons arrested committed the crime of rioting because the

officers could not possibly have observed each one’s behavior.

See Carr v. District of Columbia, 565 F.Supp. 2d 94, 99-101

(D.D.C. 2008).

Turning to the charge of parading without a permit, the

district court apparently concluded that since the offense of

parading without a permit requires a showing of intent, no
8

reasonable officer could conclude – without a dispersal order –

that the marchers were aware that the march lacked a permit. Id.

at 102-04. The court observed, moreover, that “the district has

offered no indication of how the arresting officers could

distinguish between the protestors and any other person who

might have been in the alley at the time the arrest was ordered”

(which presumably was a reason buttressing the court’s

conclusion regarding the rioting grounds for arrest as well). Id.

at 104 n.14.

The district court based its analysis of both proffered

grounds for plaintiffs’ arrests on our circuit precedent,

specifically two opinions – one, Washington Mobilization

Comm. v. Cullinane, 566 F.2d 107 (D.C. Cir. 1973), from the

Vietnam War era, and our quite recent Barham v. Ramsey, 434

F.3d 565 (D.C. Cir. 2006).

 

II

Under the District of Columbia’s criminal law, a riot is

defined as “a public disturbance involving an assemblage of 5 or

more persons which by tumultuous and violent conduct or the

threat thereof creates grave danger of damage or injury to

property or persons” (emphasis added). D.C. Code § 22-

1322(a). And it is also unlawful for anyone to engage in, incite,

or urge others to engage in a riot. Id. at § 22-1322(b), (c). 

In light of that definition, if members of the crowd were

cheering acts of violence committed by other marchers, they

would be engaging in criminal conduct. Appellees’ counsel did

not dispute that proposition; moreover, he shrewdly conceded

that the district court was in error in concluding that the police

were obliged to identify the individuals who engaged in violence

(and presumably only arrest them). And he also conceded that

the district court erred in concluding that Officer Keller’s
9

2

 If it were determined that there was probable cause to arrest the

named plaintiffs, it is not clear what effect that has on the class action,

see East Texas Motor Freight Sys., Inc. v. Rodriguez, 431 U.S. 395,

406 n.12 (1977), but in any event, that issue has not been presented.

statement that “the mob acted uniformly in celebrating the

destructive acts of individual protestors, thereby encouraging

more such acts” was only a “legally insufficient generalized

statement.” Rather, he recognized that under this court’s

precedent, officers may be able to establish that they had

probable cause to arrest an entire group of individuals if the

group is observed violating the law even if specific unlawful

acts cannot be ascribed to specific individuals. Even so, counsel

contended that the evidence in this case was inadequate, as a

matter of law, to establish that the officers could observe the

whole group.

Appellees also contend that the government did not prove

– which they assert is the government’s burden – that all of the

persons arrested in the alley were marchers. According to

appellees, the government must show that the alley was cleared

before the protestors were herded into the alley and that the

police ensured that no non-marchers entered the alley from the

back side (Columbia Road). Several of the plaintiffs claimed

that they, in fact, entered the alley by that circuitous route, but

they also admitted they were marchers – which is paradoxical

since even if some marchers entered the alley from the back side

and all marchers were legitimately considered rioters, it would

not matter how they entered the alley.2

 Only if the police should

have known (or did know) that non-marchers entered the alley

from Columbia Road could those non-marchers claim a possible

illegal arrest.

In any event, appellees’ case boils down to the proposition

that there was an insufficient showing to establish probable
10

cause that the 65-75 persons arrested – each and every one –

were engaged in the crime of rioting, even as broadly defined.

Appellees seem to contend that no arrests could take place

unless the officers could observe every single member of the

marchers and, perhaps – it is not clear – testify that each one was

either participating in vandalism or cheering it on, and

furthermore, that at the time of the arrest of the 65-75 in the

alley, no non-marchers (non-protestors) were scooped up. The

issues before us are thus considerably narrower than that which

the district court articulated – and they are really factual, not

appropriate for summary judgment. 

We do not think Cullinane and Barham support the district

court’s reasoning. Neither case involved an arrest for rioting or

encouraging a riot. In Cullinane, protestors were arrested only

for violating a “failure to move on” statute but, as appellees’

counsel recognized, we observed in that case that, “[i]f all

members of a group are arrested, the prosecutor may well be

able to prove by the testimony of policemen who were at the

scene, that there was probable cause to believe that the group as

a whole was violating the law by violence or obstruction . . . .”

566 F.2d at 121. 

In Barham, protestors were arrested for failure to obey a

dispersal order of an officer, but since no order was given, the

court considered whether the police had grounds to arrest for

unlawful assembly or for previous acts of vandalism. An

assistant police chief monitoring groups protesting the annual

meeting of the World Bank had witnessed some unidentified

demonstrators engage in scattered acts of vandalism throughout

the day. Later that day, a large group of demonstrators

converged on Pershing Park. After watching the scene for 45

minutes and despite observing “a diverse flow of human traffic

enter[ing] and exit[ing] the park,” the officer, without giving a

dispersal order, directed that everyone in the park – a group
11

numbering 386 people – be arrested. 434 F.3d at 569-70. We

held that police did not have probable cause to arrest everyone

in the park on the basis of those earlier acts witnessed by the

assistant police chief, because “[t]raffic offenses and scattered

acts of vandalism by unidentified individuals in the streets . . .

could not have incriminated all of the individuals who happened

to occupy the park” at the time of the arrest. Id. at 574. Neither

was there probable cause to arrest for an unlawful assembly as

there was no way for police to differentiate between assembled

demonstrators and others that just happened to be in the park at

the time. There was no suggestion of a riot in Barham; the

police only argued that the arrests were justified on the isolated

acts of vandalism and unlawful assembly grounds. 

Of crucial significance, we made clear that the individuals

in Barham “never operated as a cohesive unit.” Id. at 569.

Moreover, we carefully noted that “the crowd exhibited no

behavior that could allow a reasonable officer to believe

everyone present had committed a crime.” Id. at 573 (emphasis

supplied); see also id. at 574 (“[T]his case is not about a group

of lawbreakers entering an uninhabited park and then remaining

united inside.”) (emphasis supplied). To be sure, as the district

court emphasized, we did say that probable cause must be

particularized, see id. at 573, but it is clear from our opinion –

and from our previous opinion in Cullinane – that that showing

is satisfied if the officers have grounds to believe all arrested

persons were a part of the unit observed violating the law.

Turning to the evidence in our case, the key testimony as to

the behavior of the marchers as a group, as we noted, was that

of Officer Keller, whose affidavit states that as he trailed the

marchers, he saw people within the group throwing objects at

windows of several storefronts. “Each time a window was

broken,” he said, “the group cheered and its members raised

their arms.” The celebration came from “what appeared to be
12

3

 Plaintiffs suggest that a video depicting portions of the march

proves that someone from the back of the march could not see the

entire crowd. The video, however, does not even show the undisputed

acts of property destruction let alone that someone in Officer Keller’s

position could not have seen the entire crowd’s reaction to those acts.

everyone in the group.” Nevertheless, plaintiffs contend that

from his vantage point, trailing the marchers, Officer Keller

could not have seen the entire crowd and so could not

competently testify under Fed. R. Civ. P. 56(e)(1) as to whether

the entire crowd was encouraging a riot.3 But that is hardly an

issue of “competence” under the Federal Rules; courts exclude

affidavit testimony on competence grounds when the affiant is

somehow not qualified to testify on the subject. See e.g., Shakur

v. Schriro, 514 F.3d 878, 889 (9th Cir. 2008) (prison’s Pastoral

Administrator not competent under Rule 56(e) to testify about

the cost of procuring prison meals). Keller, on the other hand,

was undeniably present and it is not claimed that his vision was

impaired. He is certainly qualified to describe what he saw. See

Londrigan v. FBI, 670 F.2d 1164, 1174 (D.C. Cir. 1981) (affiant

competent under Rule 56(e) to testify to personal observations

and experiences). He may or may not have had the appropriate

vantage point but that, of course, is an issue of fact for the jury,

not a question of competence.

Insofar as appellees (or the district court) are suggesting that

no one could be “competent” to see everyone individually in a

large crowd, they are postulating an impossible burden not

drawn from our precedent. Police witnesses must only be able

to form a reasonable belief that the entire crowd is acting as a

unit and therefore all members of the crowd violated the law. A

requirement that the officers verify that each and every member

of a crowd engaged in a specific riotous act would be practically

impossible in any situation involving a large riot, particularly
13

when it is on the move – at night. To satisfy appellees’

suggested standard of proof would require virtually as many

officers as rioters – and even then it is doubtful that it could be

met. Paradoxically, appellees read the statute so as to make it

unenforceable in situations where it is most needed. To be sure,

under the standard of our cases – that the police are obliged to

show that the crowd acted unlawfully as a unit – it is possible

that an entirely innocent person would be mistaken for a rioter.

But it should be borne in mind that the legal issue is probable

cause, not ultimate conviction. Probable cause only requires a

reasonable belief of guilt, not a certitude. See Brinegar v.

United States, 338 U.S. 160, 175 (1949) (“In dealing with

probable cause, however, we deal with probabilities. These are

not technical, they are the factual and practical considerations of

everyday life on which reasonable and prudent men, not legal

technicians, act.”). 

Alternatively, appellees argue that even assuming arguendo

that it reasonably appeared to police that everyone in the street

was rioting, the police still did not have probable cause to make

the arrests in the alley. They again rely heavily on Barham. As

we noted above, in Barham the assistant police chief ordered the

arrest of everyone in the park and argued his decision was

justified because he had observed unidentified demonstrators

engaging in unlawful acts on the streets earlier in the day. 434

F.3d at 574. We easily rejected that argument in part because

evidence in the record showed that pedestrian traffic flowed

freely into the park before the mass arrest. Therefore, the police

could not have had “reasonable, particularized grounds to

believe every one of the 386 people arrested” were the same

people observed committing crimes. Id. Appellees claim the

alley is analogous to the Barham park. 

But in Barham the record showed that many people who

could not be tied to illegal activity streamed in and out of the
14

park before the mass arrest. The parties agree that there is no

affirmative evidence here of individuals not associated with the

protest being present in the alley. Appellees acknowledge this

point, but maintain that it makes no difference because the

District bears the burden of proving probable cause. Granted the

district does have the burden of proving officers had probable

cause, see Dellums v. Powell, 566 F.2d 167, 175-76 (D.C. Cir.

1977), but that burden does not oblige the District to exclude

definitively the bare possibility that there were people that

played no role in the protest in the alley before the protestors

entered. The District must show only that the officers had

reasonable grounds to believe, see Barham 433 F.3d at 574, that

everyone arrested was part of the rioting group. 

In that regard, there are material issues of fact that must be

resolved. Plaintiffs and police tell two very different stories as

to how the plaintiffs came to be arrested in the alley. And, we

think the police’s recounting of events, which we must credit at

this stage, certainly permitted the police to believe reasonably

that everyone in the alley had been a marcher.

The police affidavits stress that officers established a line on

18th Street in front of the protestors and south of the alley as

Lieutenant Riley’s Civil Disturbance Unit moved in from

behind. According to Officer Keller, as Riley’s unit approached

the crowd from behind, “the mob ran southward along 18th

Street, N.W., with members running westward into an alley

between Belmont Road, N.W., and Riley’s Cruiser. MPD

officers caught the members of the mob who ran into the alley

. . . .” Keller stated that all this took place as uninvolved

onlookers stood by undisturbed. Other police affidavits

corroborate that account. Importantly, the police accounts

uniformly state that police arrested those members of the crowd

who ran into the alley, as opposed to indiscriminately arresting

everyone they happened to find in the alley as in Barham. There
15

4

 Plaintiffs argue that the District’s brief fails to explain why out

of 250-300 marchers, only 65-75 were arrested. We are puzzled as to

why this matters. The fact that officers did not arrest everyone in the

crowd that appeared to be rioting says nothing about whether the

officers had probable cause to arrest those they did.

is also evidence that could allow a fact finder to conclude that

the police took steps to ensure that individuals not connected to

the demonstration would not be caught up in a mass arrest in the

alley. For example, the police stated that they blocked off the

Columbia Road opening to the alley, which would block the

marchers’ escape out of the alley but also, presumably,

prevented others from entering. The District also points to video

evidence which shows police officers clearing the alley of nondemonstrators prior to the protestors’ arrival.4

 

Of course, the plaintiffs dispute the officers’ account. All

of the named plaintiffs claim that they walked past the 18th

Street entrance to the alley, turned right on Belmont Road,

turned right again onto Columbia Road and then entered the

alley from the Columbia Road side. Although these plaintiffs

were, in fact, marchers – and, as we pointed out, as marchers it

would not matter how they entered the alley – if their testimony

were believed, it could cast doubt on the effectiveness of the

officers’ claimed blockage of the Columbia Road alley 

entrance. But again, that is an issue for the jury. 

* * * 

Finally, we disagree with plaintiffs (and the district court)

that the police could not lawfully complete the mass arrest

without first ordering the crowd to disperse and then giving

plaintiffs an opportunity to comply. We recognized in

Cullinane, 566 F.2d at 120 that when police face an unruly

crowd they may give a dispersal order and then arrest those who,
16

5

 As we explained in Barham, this court held that a dispersal

order was required in Dellums before police could arrest “a group of

demonstrators lawfully gathered on the Capitol steps,” Barham, 473

F.3d at 576. Because the Dellums demonstrators had permission to

assemble, we said that it would be a form of entrapment to arrest them

without first giving an opportunity to disperse. Dellums, 566 F.2d at

182-83. We did not hold that a dispersal order is required for any

group arrest. 

after reasonable opportunity to comply, fail to do so. We

continue to acknowledge that this tactic will be invaluable to

police in certain circumstances. A dispersal order might well be

necessary in a situation in which a crowd is “substantially

infected with violence,” id., or otherwise threatening public

safety, yet officers cannot reasonably believe that the crowd is

acting unlawfully as a unit. In that event, a dispersal order

might be the only means of distinguishing the wholly innocent

from the others. Indeed, that was the situation presented in

Barham and that is why we thought that officers could only deal

with the crowd as a unit by first giving an order to disperse. See

Barham, 434 F.3d at 575-76.

As useful as the dispersal order tactic may be in certain

situations, neither Cullinane, Dellums5, nor Barham establish it

as a constitutional prerequisite before every group arrest. If

police have probable cause to believe that the group they are

arresting is committing or has committed a crime, no more is

necessary. Requiring a dispersal order in addition to the

ordinary probable cause threshold would be particularly

anomalous in a case like this in which officers have reason to

believe that an entire crowd is engaged in or encouraging a riot.

In such a dangerous situation, officers may wish to quell a

disruptive situation and arrest those responsible for it, but a

dispersal order – even if effective, which is doubtful – would
17

6

 Plaintiffs contend that First Amendment principles prohibited

their arrest without first being given a chance to disperse. In sum,

plaintiffs contend that they were marching peacefully and if peaceful

marchers can be arrested without warning because some other

protestors resorted to violence, it will chill First Amendment rights.

Aple. Br. at 36-40. The premise of this argument is fundamentally

flawed, however, because viewing the facts in the light most favorable

to the District, as we must here, it appeared to officers as if the entire

crowd was rioting or encouraging riotous acts. And “where

demonstrations turn violent, they lose their protected quality as

expression under the First Amendment.” Grayned v. City of Rockford,

408 U.S. 104, 116 (1972). 

7

 Appellees point to the District’s policy, which is not to make

arrests for parading without a permit. However, a police officer can

act consistently with the Fourth Amendment by making an arrest that

is supported by probable cause, even if prohibited by state law, see

Virginia v. Moore, 128 S. Ct. 1598, 1607 (2008) (so holding), so the

District’s policy is also immaterial in our Fourth Amendment analysis.

allow the putative rioters to escape. A refusal to disperse is,

therefore, not one of the elements of a rioting charge.6 

III

In addition to ruling that the officers could not have had

probable cause to arrest the protestors for rioting, the district

court held that they could not have had probable cause to make

arrests for parading without a permit. The District contends on

appeal that this too was erroneous.7 On this point we disagree

with the District. 

We have held that to be criminally liable for parading

without a permit, one must do so knowingly. See Sheehan, 512

F.3d at 631. Accordingly, officers who make such an arrest
18

must have reasonable grounds to believe that the suspect 1) took

part in a parade, 2) without a permit, 3) and did so, knowing no

permit was granted. In this case, there is no dispute that the

demonstrators engaged in a parade and did so without a permit.

But appellees do dispute vigorously that the police officers

could reasonably believe that the protestors knew that no permit

had been given, since no dispersal order mentioning the lack of

permit was given. Just as we explained with regard to the

grounds for arrest for rioting, a dispersal order is not a sine qua

non for arresting for marching without a permit. If the District

could have shown that the protestors had the requisite intent

through other evidence, that would have sufficed. 

Still, even if the lack of a dispersal order did not, in itself,

render these arrests unlawful, the District was presented with a

formidable challenge in showing that officers could reasonably

believe that all of the protestors knew no permit was granted.

The police certainly did nothing to otherwise inform the

marchers that their demonstration was not permitted by the

District. So the police had no direct evidence upon which to

conclude that everyone arrested had the requisite intent.

Nonetheless, the District argues that under the circumstances it

was reasonable for police to infer that all of the marchers knew

that this parade did not have a permit. It is claimed that the

protest march was apparently spontaneous; that the march began

at 11:30 at night and proceeded through a residential

neighborhood; that the parade’s participants were carrying

torches, setting fires, and placing obstacles in the street; and

finally, that the protest culminated in a riot. 

We are not persuaded that the time or character of the

march is at all probative as to the marchers’ presumed

knowledge that a permit was lacking. Why would a marcher

believe a permit would not be granted to march on 18th Street,

even though it is a partly residential area, or that the District
19

would not authorize a night march? And that a demonstration

turns violent is hardly evidence that shows it more likely than

not that a permit was not granted. Obviously, an authorized

march or demonstration could turn violent as well as one that

was not authorized.

That leaves the District with its spontaneity argument – and

that might have been sufficient but for the distribution of the

flier, which necessarily suggested to the group earlier planning

for the march. We, therefore, affirm the district court’s rejection

of the alternative non-permit ground for arrest and remand on

the issue of probable cause to arrest for rioting only. 

 So ordered.
SENTELLE, Chief Judge, concurring in part and dissenting

in part: I fully join the opinion of the court in all respects

concerning the crime of rioting, and therefore concur in the

disposition reversing the summary judgment as to the arrest on

the rioting charges. However, as to the summary judgment on

the arrest for parading without a permit in violation of 24

DCMR § 707.7, I disagree with the court’s analysis as expressed

in the penultimate paragraph of the opinion and therefore dissent

from the affirmance of the grant of summary judgment. It is

uncontested that the protestors’ conduct met the first two

elements for such a violation: the protestors were participating

in a march and the District of Columbia had not issued a permit

for the march. The only element at issue is the mens rea

requirement of “knowing.” The majority asks, “Why would a

marcher believe a permit would not be granted to march on 18th

Street, even though it is a partly residential area, or that the

District would not authorize a night march?” I would state the

question differently: “Why would anyone believe that the

District would grant a permit for a night march through a partly

residential area?” It seems to me that the police could have

inferred that the protestors knew that no permit had been issued

from the time and location of the march.

It may be that the court’s reasoning would support a verdict

on this count in favor of appellants after trial, but we review the

case on summary judgment. The question on summary

judgment is whether there is “no genuine issue as to any

material fact.” It is true that under Rule 56, “the trial judge must

direct a verdict if, under the governing law, there can be but one

reasonable conclusion as to the verdict.” Anderson v. Liberty

Lobby, Inc., 477 U.S. 242, 250 (1986). It is equally true that

“[i]f reasonable minds could differ as to the import of the

evidence, however, a verdict should not be directed.” Id. at 250-

51. In making the necessary determination “at the summary

judgment stage the judge’s function is not [her]self to weigh the
2

evidence and determine the truth of the matter but to determine

whether there is a genuine issue for trial.” Id. at 249. 

As the evidence to me discloses a reasonable inference

opposite than that drawn by the majority and the district court,

and as I deem us all reasonable, it appears to me that reasonable

minds can differ. Weighing the evidence and the inferences is

not for us, but for a trier of fact. I would therefore reverse and

remand the summary judgment as to this issue, as well as the

first. 
GRIFFITH, Circuit Judge, concurring in part and 

concurring in the judgment: I would also reverse the district 

court and join fully Parts I and III of the court’s opinion. I 

write separately because I disagree with the probable cause 

standard the majority uses in Part II. As Supreme Court 

precedent affirms, the Fourth Amendment requires an 

individualized showing of probable cause before arrest. The 

majority unnecessarily calls into question the heretofore 

straightforward application of that standard in this circuit. 

I. 

The Fourth Amendment provides, in relevant part, “The 

right of the people to be secure in their persons . . . against 

unreasonable . . . seizures, shall not be violated, and no 

Warrants shall issue, but upon probable cause, supported by 

Oath or affirmation, and particularly describing . . . the 

persons or things to be seized.” U.S. CONST. amend. IV. 

Explaining the Fourth Amendment’s requirement of a 

particularized showing of probable cause, the Supreme Court 

in Ybarra v. Illinois stated that “a search or seizure of a 

person must be supported by probable cause particularized 

with respect to that person.” 444 U.S. 85, 91 (1979). 

Similarly, the Court in Maryland v. Pringle emphasized that 

“the belief of guilt must be particularized with respect to the 

person to be searched or seized.” 540 U.S. 366, 371 (2003). In 

other words, the police must have a reasonable and 

particularized belief that each individual arrested committed a 

crime. As the Ybarra Court made clear, “This requirement 

cannot be undercut or avoided by simply pointing to the fact 

that coincidentally there exists probable cause to search or 

seize another.” 444 U.S. at 91. Before today, our case law did 

not suggest “that one who has violated no law may be arrested 

for the offenses of those who have been violent or 

obstructive.” Wash. Mobilization Comm. v. Cullinane, 566 

F.2d 107, 120 (D.C. Cir. 1977). Today’s decision suggests 

just that. 
2 

Describing what must precede an arrest when a crowd of 

political demonstrators has gotten out of hand, the majority 

creates a standard of probable cause less demanding than 

Ybarra and Pringle for circumstances in which the police 

cannot say anything more than the arrested person was part of 

a group some of whose members were rioting. “Police 

witnesses,” the majority concludes, “must only be able to 

form a reasonable belief that the entire crowd is acting as a 

unit and therefore all members of the crowd violated the law.” 

Slip Op. at 12. By this standard, the police are permitted to 

conclude that all members of the crowd were breaking the 

law, not because of a particularized showing that each of its 

members was rioting, but because of an officer’s “reasonable 

belief that the entire crowd is acting as a unit.” Id. 

It is far from clear what the majority means when it 

speaks of a “crowd . . . acting as a unit.” I would have no 

quarrel with the majority’s approach if it meant there must be 

probable cause that every individual in the crowd acted in 

concerted lawlessness with the rest of the group. But the 

majority refuses to ask this of the police. Not only does the 

majority avoid the language of Ybarra and Pringle calling for 

particularized probable cause that the arrested person 

committed a crime, but it flatly rejects that standard in this 

case. The majority protests that “[a] requirement that the 

officers verify that each and every member of a crowd 

engaged in a specific riotous act would be practically 

impossible in any situation involving a large riot . . . .” Id. The 

issue, however, is not what is practical but what the Fourth 

Amendment requires, and in this case the majority departs 

from the Supreme Court’s consistent instruction that 

individualized probable cause must precede arrest. 
3 

The majority takes the term “unit” from our decisions in 

Cullinane and Barham v. Ramsey, 434 F.3d 565 (D.C. Cir. 

2006), but neither of those cases suggests that the Fourth 

Amendment permits an arrest of a person based on anything 

less than particularized probable cause. Calling the group or 

crowd a “unit” does not alter the probable cause calculus. 

Police don’t arrest units. They arrest persons, and the Fourth 

Amendment requires they do so only upon an individualized 

determination that the person arrested acted unlawfully. The 

majority’s approach ultimately fails because whatever else it 

may mean to have a reasonable belief that a crowd acted “as a 

unit,” it cannot be the basis for the arrest of a member of that 

crowd, unless there is also a particularized showing that the 

person broke the law. 

That the Fourth Amendment bars police from arresting a 

person solely because he or she is part of a group that includes 

others who have committed crimes should be undisputed. But 

the majority permits just that outcome. No case relied upon by 

the majority stands for the proposition for which this case will 

be cited: that police may lawfully execute mass arrests based 

upon assessments of group behavior and not upon 

particularized determinations about individual conduct. 

Because the Fourth Amendment demands more from the 

police than the majority requires, I cannot join Part II of the 

court’s opinion. 

II. 

The issue before the district court on plaintiffs’ motion 

for summary judgment was whether the police had probable 

cause to arrest every demonstrator on the basis of Officer 

Keller’s observations. By granting summary judgment, the 

district court erred in two ways. 
4 

First, the court disregarded a genuinely disputed issue of 

material fact. “A genuine issue of fact derives from the 

‘evidence [being] such that a reasonable jury could return a 

verdict for the nonmoving party’ . . . resolving all ambiguities 

and drawing all factual inferences in favor of the nonmoving 

party.” Moore v. Hartman, 571 F.3d 62, 66 (D.C. Cir. 2009) 

(quoting Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 247 

(1986)). Keller said he saw every member of the crowd 

commit the crime of rioting. His statements on this point were 

unequivocal: 

- “Each time a window was broken, the group cheered 

and its members raised their arms.” 

- “It appeared that the entire group was engaging in the 

celebrations as they moved . . . .” 

- “The mob then cheered and its members raised their 

arms in celebration.” 

- “Someone in the group hurled a rock or brick through 

the window of [the Metropolitan Police Department’s 

Latino Liaison Unit] Office . . . which was once again 

followed by loud cheering and arm waving from what 

appeared to be everyone in the group. I could see and 

hear this clearly from inside Cruiser 18 . . . .” 

Decl. of Patrick Keller ¶ 6 (Feb. 26, 2008). Not surprisingly, 

plaintiffs denied they engaged in rioting, thus disputing that 

Keller observed every member of the crowd. See, e.g., 

Plaintiffs’ Motion for Partial Summary Judgment on Liability 

at 5–6, Carr v. District of Columbia, 565 F. Supp. 2d 94 

(D.D.C. 2008) (No. 06-00098) (“[T]he police had no evidence 

identifying particular individuals who had engaged in the 

criminal acts.”). The legal issue—whether there was 

particularized probable cause to arrest plaintiffs—turns on 

whether Keller did see every individual in the crowd commit 

a crime. 
5 

The assertion that one officer could see each of the 300 

individual marchers is audacious. Regardless, in considering 

plaintiffs’ motion for summary judgment, it was error for the 

district court not to view Keller’s statements in the light most 

favorable to the District. “Credibility determinations, the 

weighing of the evidence, and the drawing of legitimate 

inferences from the facts are jury functions, not those of a 

judge . . . . The evidence of the non-movant is to be believed, 

and all justifiable inferences are to be drawn in his favor.” 

Liberty Lobby, 477 U.S. at 255. Keller says he saw each 

person in the march celebrate acts of violence. Because it is 

possible that a reasonable jury could credit his testimony, the 

district court erred by failing to take Officer Keller at his 

word. 

Second, the district court incorrectly held that Keller’s 

testimony was insufficient as a matter of law because it failed 

to establish the particularity called for in Ybarra. The court 

concluded, “These kinds of generalized statements are legally 

insufficient to establish probable cause. . . . Nowhere does the 

District make any effort to ascribe misdeeds to the specific 

individuals arrested.” Carr v. District of Columbia, 565 F. 

Supp. 2d 94, 100 (D.D.C. 2008) (internal quotation marks and 

citation omitted). To the contrary, Keller’s statements 

accomplish precisely what the district court concluded they 

did not. Keller ascribed misdeeds to the specific individuals 

arrested. He said he saw every member of the crowd commit a 

crime. In light of Keller’s clear testimony about the criminal 

misconduct of each person in the crowd, the district court 

should not have granted summary judgment. 

Ruling on this narrow ground corrects the district court’s 

error without suggesting police may conduct mass arrests 

without individualized probable cause.