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ADVANCE SHEET HEADNOTE

March 11, 2019

2019 CO 18

No. 18SA263, People v. Threlkel—Investigatory Stop—Grounds for Stop or 

Investigation—Fellow-Officer Rule.

An extensive narcotics investigation culminated in arrest warrants for the 

defendant and her significant other based on their alleged distribution of controlled 

substances. While attempting to execute the warrants, deputies observed a truck 

belonging to the defendant’s significant other driving away from the residence shared by 

the couple. The deputies suspected that the defendant was a passenger in the truck. As 

the deputies tried to stop the truck, it evaded them. At one point, the deputies observed 

a white bag fly out of the passenger window, which supported their belief that there was 

a passenger in the truck. The truck eventually stopped within a mile of the home. Inside, 

they located the defendant’s significant other, but not the defendant. Moments later, 

however, the defendant was spotted a couple of hundred yards away, attempting to hitch 

a ride. It was a frigid and snowy night, the roads were slippery, and there was no easy 

access on foot between the home and the location of the stop. A deputy who recognized 

the defendant detained her, and she was later arrested on her outstanding warrant. 
The trial court suppressed all evidence and observations derived from the 

defendant’s stop, finding that the deputies lacked reasonable, articulable suspicion to 

detain her. Later, the trial court explained that its suppression order included the 

deputies’ observations and investigation before they contacted the defendant. 

The supreme court reverses. It concludes that the deputies had reasonable, 

articulable suspicion to stop the defendant. It further concludes that the trial court lacked 

authority to suppress the deputies’ observations and investigation before they contacted 

the defendant. 
The Supreme Court of the State of Colorado

2 East 14th Avenue • Denver, Colorado 80203

2019 CO 18

Supreme Court Case No. 18SA263

Interlocutory Appeal from the District Court

Arapahoe County District Court Case No. 17CR3478

Honorable Andrew C. Baum, Judge

______________________________________________________________________________

Plaintiff-Appellant:

The People of the State of Colorado,

v.

Defendant-Appellee:

Amber Anne Threlkel.

______________________________________________________________________________

Order Reversed

en banc

March 11, 2019

______________________________________________________________________________

Attorneys for Plaintiff-Appellant:

George H. Brauchler, District Attorney, Eighteenth Judicial District

Jacob Edson, Chief Deputy District Attorney

Centennial, Colorado

Attorneys for Defendant-Appellee:

Megan A. Ring, Public Defender

Alaina Almond, Deputy Public Defender

Stephanie Howard, Deputy Public Defender

Centennial, Colorado

JUSTICE SAMOUR delivered the Opinion of the Court.
2

¶1 As part of an extensive narcotics investigation that spanned almost all of 2017, law 

enforcement deputies obtained arrest warrants for the defendant, Amber Anne Threlkel, 

and her significant other, Robert Allen, based on their alleged distribution of controlled 

substances. The deputies executed the warrants on December 7, 2017. That evening, they

observed a truck owned by Allen leave the residence he shared with Threlkel; they

suspected that Allen and Threlkel were both in the truck. As the deputies attempted to 

perform a traffic stop, the truck evaded them, causing them to momentarily lose sight of 

it. But they eventually spotted the truck again, stopped it, and apprehended the driver, 

Allen, within a mile of the home. Although there was no passenger in the truck, Threlkel 

was located a couple of hundred yards from it, attempting to hitch a ride. It was a frigid

and snowy night, the roads were slippery, and there was no easy access on foot between 

the home and the location of the stop. A deputy who recognized Threlkel detained her. 

Threlkel was later arrested pursuant to her outstanding warrant. 

¶2 Threlkel was charged with multiple drug-related offenses. Before trial, she filed 

several motions to suppress. The trial court granted one of them, finding that the 

deputies lacked reasonable, articulable suspicion to stop her. The court thus suppressed 

all evidence and observations derived from Threlkel’s stop, including her statements. It 

later clarified its ruling at the prosecution’s request. It explained that its suppression 

order included the deputies’ observations and investigation before they contacted 

Threlkel. Therefore, observed the court, the prosecution would not be allowed to 

mention at trial that Threlkel was even at the location where she was detained. 
3

¶3 We now reverse. We conclude that the deputies had reasonable, articulable 

suspicion to detain Threlkel. We further conclude that, even if the trial court’s contrary 

ruling had been correct, there is no authority to suppress the deputies’ observations and 

investigation before they contacted Threlkel. Accordingly, we remand this matter to the 

trial court for further proceedings consistent with this opinion. 

I. Facts and Procedural History

¶4 In early 2017, deputies from the Arapahoe County Sheriff’s Office narcotics team

launched an extensive drug-related investigation of Threlkel and Allen. At some point, 

the deputies obtained arrest warrants for the couple based on their alleged distribution 

of controlled substances. At approximately 7 p.m. on December 7, 2017, Deputy Wood 

and other narcotics deputies were surveilling the home shared by Threlkel and Allen, 

looking for an opportunity to execute the warrants. They were hoping to catch Threlkel 

and Allen away from the home. Allen’s truck was parked in front of the residence. While 

the deputies did not see anyone enter the truck, they noticed that it remained outside the 

home with its headlights on for a long period of time. This led Deputy Wood to suspect 

that both Allen and Threlkel were in the truck. 

¶5 When the truck drove away from the home, the narcotics team asked Deputy 

Rivers, a patrol deputy, to conduct a traffic stop and contact the occupants of the truck 
4

pursuant to the outstanding arrest warrants.1 Although he did not have information 

about the identity of the truck’s occupants, Deputy Rivers was told that the driver was 

believed to be male and that the passenger was believed to be female. 

¶6 As Deputy Rivers arrived at the residential community where the home is located, 

he started looking for the truck. It was snowing, there were freezing temperatures, and 

the roads were icy. Upon spotting the truck, Deputy Rivers turned around so that he 

could get behind it. While he and other deputies were in pursuit, the truck started driving

erratically and evading them. The truck then pulled over, only to take off again. The 

deputies temporarily lost sight of it, but located it shortly thereafter. They subsequently 

observed the truck crash through a private gate. They also saw what appeared to be a 

white bag fly out of the passenger window, which supported their belief that there was a 

passenger in the truck. The truck eventually stopped within a mile of the home and Allen 

was apprehended. There was no passenger in the truck. 

¶7 Moments after Allen was detained, a nearby driver informed Deputy Rivers that 

she had just seen a white female in a white coat walking southbound, away from the 

location of the truck, trying to hitch a ride. Deputy Rivers then saw a white female 

wearing a white coat on foot within a couple of hundred yards of where the truck had 

stopped; there was no easy access by foot between the home and that area. Because Allen 

 

1 Deputy Wood testified that they had other grounds to stop the truck: its unlawfully 

altered suspension and the lack of a visible front license plate. 
5

was being held in his patrol car, Deputy Rivers decided to contact the female on foot. 

However, a member of the narcotics team, Deputy Daly, beat him to the punch. 

¶8 Deputy Daly did not testify at the hearing. However, Deputy Rivers was aware 

that Deputy Daly had been involved in this investigation, knew about the arrest warrants, 

and could recognize Threlkel. More importantly, by the time Deputy Rivers reached the 

female, Deputy Daly “had already visually identified her” as Threlkel. Deputy Daly 

temporarily detained Threlkel in order to confirm her arrest warrant. Once the warrant 

was verified, Threlkel was arrested. 

¶9 Threlkel was subsequently charged with multiple drug-related offenses. Before 

trial, she filed three motions to suppress. The trial court held an evidentiary hearing 

during which the prosecution presented testimony from Deputy Rivers and Deputy 

Wood. Threlkel did not present any testimonial evidence. 

¶10 The trial court found that both deputies were credible and that their testimony had 

no reliability issues. Yet, it ruled that the deputies violated Threlkel’s rights under the 

Fourth Amendment because they lacked a reasonable, articulable suspicion to detain her. 

The trial court seemed troubled by the fact that Deputy Daly did not testify since he was 

the deputy “who [was] able to identify Ms. Threlkel as being the one the warrant was 

valid for.” Notably, the trial court acknowledged Deputy Rivers’s uncontroverted 

testimony that “Deputy Daly . . . knew that the white female that was pointed out by [the]

unknown driver was Ms. Threlkel.” But it nevertheless suppressed all evidence and 

observations derived from Threlkel’s stop, including her statements, because it felt that
6

there were important details missing in the testimony provided by Deputies Rivers and 

Wood. 

¶11 At a later status hearing, the trial court clarified its ruling at the prosecution’s 

request. It indicated that its suppression order went beyond the evidence and 

observations derived from Threlkel’s stop—the order also included the deputies’ 

observations and investigation before they contacted Threlkel. According to the court, 

Threlkel was “not arrested at the scene” because “[t]here’s no evidence to indicate that 

she was even there.” Therefore, concluded the court, the prosecution would not be 

allowed to introduce evidence at trial that the deputies contacted Threlkel at all. 

¶12 The prosecution then brought this interlocutory appeal.2 

II. Analysis

¶13 The prosecution argues that the trial court erred both in ruling that the deputies 

lacked reasonable, articulable suspicion to detain Threlkel and in suppressing evidence 

preceding their contact with her. We agree. We conclude that the deputies had

reasonable, articulable suspicion to detain Threlkel. We further conclude that, even if the 

trial court’s contrary ruling had been correct, there is no authority to suppress the 

 

2 This interlocutory appeal was properly filed pursuant to section 16-12-102(2), C.R.S. 

(2018) (requiring the People to certify that the appeal is not taken for purposes 

of delay and that the evidence is a substantial part of the proof of the charge pending 

against the defendant), and C.A.R. 4.1(a) (same). 
7

deputies’ observations and investigation before they contacted Threlkel. Accordingly, 

we reverse and remand for additional proceedings consistent with this opinion.

3 

¶14 We first set forth the applicable standard of review, followed by the relevant legal 

principles. We then address the merits of the prosecution’s appeal, discussing in turn the 

trial court’s finding of no reasonable, articulable suspicion and the trial court’s 

suppression of the deputies’ observations and investigation preceding their contact with 

Threlkel. 

A. Standard of Review

¶15 Our review of a trial court’s order addressing a defendant’s motion to suppress 

involves “a mixed question of law and fact.” People v. Gothard, 185 P.3d 180, 183 (Colo. 

2008). We defer to the trial court’s factual findings and do not disturb them “if they are 

supported by competent evidence in the record.” People v. Castaneda, 249 P.3d 1119, 1122 

(Colo. 2011). However, “the trial court’s legal conclusions are subject to de novo review.” 

People v. Pitts, 13 P.3d 1218, 1222 (Colo. 2000).

B. Relevant Legal Principles

¶16 The Fourth Amendment to the United States Constitution protects individuals 

against unreasonable searches and seizures by police. People v. Cox, 2018 CO 88, ¶ 7, 429 

P.3d 75, 78. But the Fourth Amendment does not prohibit all contact of citizens by law 

 

3 In a per curiam order, we previously denied Threlkel’s motion to dismiss this appeal as 

untimely.
8

enforcement. People v. Fields, 2018 CO 2, ¶ 11, 411 P.3d 661, 665. Rather, it aims “to

prevent arbitrary and oppressive interference by enforcement officials with the privacy 

and personal security of individuals.” Imm. & Nat. Serv. v. Delgado, 466 U.S. 210, 215 

(1984) (quoting United States v. Martinez-Fuerte, 428 U.S. 543, 554 (1976)). 

¶17 There are “two distinct levels of seizure of a person” that implicate the Fourth 

Amendment: an investigatory stop and an arrest. Fields, ¶ 12, 411 P.3d at 665. The former 

is the “less intrusive of the two.” Id. It is justified when there is “reasonable articulable 

suspicion to believe that the detainee is committing, has committed, or is about to commit 

a crime,” and its scope is limited “to a brief detention to confirm or dispel that suspicion.” 

Id. The latter is the “more intrusive of the two.” Id. It is justified when there is “probable 

cause to believe a crime has been committed by the detainee.” Id. In this case, we are 

concerned only with the less intrusive type of seizure—an investigatory stop. 

¶18 An officer’s investigatory stop complies with the Fourth Amendment when three 

criteria are met: (1) there is “an articulable and specific basis in fact for suspecting (i.e., a 

reasonable suspicion) that criminal activity has taken place, is in progress, or is about to 

occur”; (2) the purpose of the intrusion is reasonable; and (3) the intrusion’s character and 

scope are “reasonably related to its purpose.” People v. Reyes-Valenzuela, 2017 CO 31, ¶ 11, 

392 P.3d 520, 522–23 (quoting People v. Salazar, 964 P.2d 502, 505 (Colo. 1998)). Because 

the trial court found that the first prong—reasonable, articulable suspicion—was not 

satisfied, it did not address the second and third prongs. Hence, only the first prong is at 

issue in this appeal. 
9

¶19 To determine whether an officer had a reasonable, articulable suspicion to conduct 

an investigatory stop, we consider “whether there were specific and articulable facts 

known to the officer, which taken together with reasonable inferences from these facts, 

created a reasonable suspicion of criminal activity to justify the intrusion into the 

defendant’s personal security.” Id. at ¶ 12, 392 P.3d at 523 (quoting Salazar, 964 P.2d at

505). This requires us to consider the totality of the circumstances. Id. Rather than focus 

on the subjective intent of the officer, we objectively analyze whether, under all the 

circumstances present, a reasonable and articulable suspicion existed. Id. 

¶20 An officer is entitled to draw reasonable inferences from all the circumstantial 

evidence “even though such evidence might also support other inferences.” Id. at ¶ 14, 

392 P.3d at 523 (quoting Castaneda, 249 P.3d at 1122). It is for this reason that the Supreme 

Court has cautioned against engaging in a “divide-and-conquer analysis” that results in 

the dismissal of factors simply because they have plausible innocent explanations. Id.

(quoting United States v. Arvizu, 534 U.S. 266, 274–75 (2002)). Indeed, a reasonable, 

articulable suspicion may be present “even where innocent explanations are offered for 

conduct.” Id. (quoting Castaneda, 249 P.3d at 1122). Nor can we discount acts which, in 

isolation, appear to be innocent. Id. at ¶ 13, 392 P.3d at 523. Several such acts “may add 

up to a reasonable, articulable suspicion of criminal activity.” Id. As the United States 

Supreme Court has recognized, “innocent behavior frequently will provide the basis for 

a showing of probable cause,” Illinois v. Gates, 462 U.S. 213, 243 n.13 (1983), which is a 

more demanding standard than reasonable, articulable suspicion. The relevant inquiry 
10

is not whether the defendant’s conduct is innocent or guilty, “but the degree of suspicion 

that attaches to particular types of noncriminal acts.” Reyes-Valenzuela, ¶ 13, 392 P.3d at 

523 (quoting United States v. Sokolow, 490 U.S. 1, 10 (1989)).

¶21 When we consider a challenge to an investigatory stop, we are not limited to an 

officer’s observations because an officer is entitled to rely on information supplied by 

another person, including a fellow officer. See id. at ¶ 15, 392 P.3d at 523. An officer who 

does not personally possess reasonable, articulable suspicion may still lawfully make an 

investigatory stop under the fellow-officer rule if: “(1) he acts at the direction or as a result 

of communications with another officer, and (2) the police as a whole possess a sufficient 

basis to make the [stop].” People v. Arias, 159 P.3d 134, 139 (Colo. 2007). “The purpose of 

the fellow officer rule is to allow law enforcement agencies to work together as a team,” 

instead of requiring that each officer personally and independently “possess the 

particularized information necessary to make the [stop].” Id. When an investigation is 

expanded so as to include officers not at the scene of an alleged crime, the fellow-officer 

rule “operates to integrate those outside officers and make them part of the coordinated 

investigation.” People v. Swietlicki, 2015 CO 67, ¶ 27, 361 P.3d 411, 416 (quoting Grassi v. 

People, 2014 CO 12, ¶ 14, 320 P.3d 332, 336). Through the rule, “information that the police 

possess as a whole” is “impute[d] . . . to an individual officer.” Grassi, ¶ 13, 320 P.3d at 

336. 

¶22 While the fellow-officer rule “impute[s] information from officers who possess it 

to those who do not,” we have made clear that “it does not require a linear chain of 
11

communication from one officer to the next.” Id. at ¶ 17, 320 P.3d at 337. Instead, “the 

rule pools the collective knowledge of officers” working together as a cohesive unit in a 

coordinated investigation. Id. Moreover, so long as the police remain engaged in such a 

coordinated investigation, “the rule encompasses information that the police as a whole 

possess at the time of the relevant action,”—i.e., at the time of the challenged search or 

seizure. Id. at ¶ 18, 320 P.3d at 337. 

C. Application

1. The Deputies Had Reasonable, Articulable Suspicion to Stop Threlkel

¶23 The first question we must address is whether the trial court erred in finding that 

the deputies lacked reasonable, articulable suspicion to stop Threlkel. We conclude that 

it did. 

¶24 The trial court faltered from the outset when it determined that no reasonable, 

articulable suspicion could be shown without testimony from Deputy Daly, the deputy 

who stopped Threlkel. As the trial court acknowledged, Deputy Rivers credibly testified 

that he was aware that Deputy Daly had been involved in this investigation and knew 

both that Threlkel had an outstanding arrest warrant and that “the white female that was 

pointed out by [the] unknown driver was Ms. Threlkel.” This uncontroverted testimony,

alone, established reasonable, articulable suspicion to stop Threlkel.

¶25 But the trial court reasoned that this testimony was not sufficient because it felt 

that certain important details were missing. For example, it pointed out that it lacked 

information related to: the fact that there was only one person found in the truck and 
12

there were “no footprints that could potentially tie Ms. Threlkel and her location to 

getting out of the truck”; “how long the truck was stopped or whether it was even 

possible for someone to get out of the truck” before Allen was detained; whether there 

was enough time for someone to exit the truck while the deputies lost sight of it during 

their pursuit; and where the deputies lost sight of the truck during their pursuit and 

whether there were footprints in that area. 

¶26 The trial court misapplied the reasonable, articulable suspicion standard. In effect, 

the trial court required the deputies to rule out the potential innocent alternative: that the 

female stopped was someone other than Threlkel who just happened to be walking and 

asking for a ride, in a residential community, during a frigid and snowy night, less than 

a mile away from her home, and just a couple of hundred yards from the location where 

the truck was stopped and Allen was detained. However, the fact that an innocent 

explanation may be imagined does not defeat the deputies’ reasonable, articulable 

suspicion. See Reyes-Valenzuela, ¶ 14, 392 P.3d at 523. Instead, the deputies were entitled 

to draw reasonable inferences from all the circumstantial evidence even if the evidence 

might also support other inferences. See id. The proper inquiry was whether, considering

all the circumstances together, the deputies had an objectively reasonable basis to believe 

that the female they stopped was Threlkel. 

¶27 Here, it is clear that, even without the missing details identified by the trial court,

the deputies had a reasonable, articulable suspicion to believe that the female they 

stopped was Threlkel:
13

• Threlkel and Allen were the subjects of a nearly year-long narcotics 

investigation that culminated in their arrest warrants. 

• The truck had earlier been parked outside the home for some time with its

headlights on.

• As the truck evaded them, the deputies observed what appeared to be a white 

bag thrown out of the front passenger window, which supported their belief 

that there was a passenger inside. 

• When the deputies finally stopped the truck, they confirmed that Allen was the 

driver. 

• Although there was no passenger in the truck, the deputies were aware that 

they had temporarily lost sight of it during their pursuit. 

• Shortly after detaining Allen, the deputies saw a white female within a couple 

of hundred yards from the truck. 

• Both she and the truck were within a mile of the home. 

• There was no easy access by foot from the home to the area where the deputies 

spotted her. 

• She was on foot, moving away from the truck, and attempting to hitch a ride. 

• And this was a residential community; it was a frigid and snowy night; and the 

roads were slippery. 

In short, there were specific and articulable facts known to the deputies, which 

considered together and in conjunction with the fair inferences drawn from those facts, 

created a reasonable suspicion that the female spotted shortly after Allen’s detention was

Threlkel.

¶28 The trial court seemed to give short shrift to these facts and inferences because

Deputy Rivers did not know what Threlkel looked like and the record does not reflect

when he was notified that the female contacted was identified as Threlkel. But Deputy 
14

Rivers did not stop Threlkel—Deputy Daly did. And, as we mentioned, the evidence at 

the hearing indisputably established, and the trial court acknowledged, that Deputy Daly

was involved in this investigation and knew what Threlkel looked like and that she was 

wanted on an arrest warrant. 

¶29 In any event, to the extent the trial court focused on Deputy Rivers’s personal 

knowledge, it erred in finding that it was insufficient to justify Threlkel’s stop. The 

knowledge personally possessed by Deputy Rivers, though limited, was sufficient to 

form a reasonable, articulable suspicion that the female located just a couple of hundred 

yards from the truck had exited the truck during or after the deputies’ pursuit and was 

the person the narcotics team was attempting to arrest. Under all the circumstances, that 

was a reasonable inference, if not the most reasonable inference, for Deputy Rivers to 

draw. 

¶30 There is an additional, independent ground to support our determination that 

Deputy Rivers had a reasonable, articulable suspicion to stop Threlkel: the fellow-officer 

rule. The trial court applied this rule, but did so incorrectly. We conclude that the rule 

imputed the collective knowledge of all the narcotics deputies to Deputy Rivers because 

both of its requirements were met. See Swietlicki, ¶ 27, 361 P.3d at 416. First, Deputy 

Rivers acted at the direction of or as a result of communications with other deputies. Id.

Specifically, the narcotics deputies asked Deputy Rivers to conduct a traffic stop of the 

truck and communicated to him that they believed there were two occupants in the truck, 

a male driver and a female passenger, and that both had outstanding warrants for their 
15

arrest. Second, at the time of the challenged seizure, the narcotics team, as a whole, 

possessed a reasonable, articulable suspicion to stop Threlkel and to believe that the 

female spotted shortly after Allen’s detention was, in fact, Threlkel. Id. 

2. No Authority Exists to Suppress Evidence Gathered Prior to

Threlkel’s Stop

¶31 Having concluded that the trial court erred in finding there was no reasonable, 

articulable suspicion to stop Threlkel, the remaining question is whether it had authority 

to suppress evidence obtained before Threlkel was contacted. We conclude that it did

not.

¶32 A few weeks after excluding all evidence and observations derivative of Threlkel’s 

stop, the trial court compounded the error by extending its suppression order to any 

observations and investigation preceding Threlkel’s stop. The trial court did not cite any 

authority in support of this ruling, and our research has unearthed none. 

¶33 The United States Supreme Court adopted the exclusionary rule to give effect to 

the Fourth Amendment’s guarantee against unreasonable searches and seizures. Casillas 

v. People, 2018 CO 78M, ¶ 19, 427 P.3d 804, 809–10. But the exclusionary rule is limited in 

scope: It prohibits “the use of improperly obtained evidence at trial, as well as evidence 

later discovered and found to be derivative of an illegality.” Id. (emphasis added) (internal 

citations omitted). It has never been applied to suppress evidence obtained before an 

illegality occurred. Such application would be inconsistent with the rule’s purpose “to 

deter deliberate, reckless, or grossly negligent conduct, or in some circumstances 

recurring or systemic negligence.” Herring v. United States, 555 U.S 135, 144 (2009). 
16

Hence, in addition to incorrectly finding that the deputies lacked reasonable, articulable 

suspicion to stop Threlkel, the trial court mistakenly suppressed evidence obtained 

before Threlkel was contacted. 

III. Conclusion

¶34 We conclude that the trial court erred in finding that the deputies lacked 

reasonable, articulable suspicion to stop Threlkel. We further conclude that the trial court 

aggravated that error by extending its suppression order to include any observations and 

investigation preceding the stop. Accordingly, we reverse the trial court’s suppression 

order and remand the matter for further proceedings consistent with this opinion.