United States Court of Appeals 

For the First Circuit 

No. 16-2009 

UNITED STATES, 

Appellee, 

v. 

HECTOR SERRANO-ACEVEDO, 

Defendant, Appellant. 

No. 16-2049 

UNITED STATES, 

Appellee, 

v. 

VIRGILIO DIAZ-JIMENEZ, 

Defendant, Appellant. 

APPEALS FROM THE UNITED STATES DISTRICT COURT 

FOR THE DISTRICT OF PUERTO RICO 

[Hon. Juan M. Pérez-Giménez, U.S. District Judge] 

Before 

Lynch, Kayatta, and Barron, 

Circuit Judges. 
 Rafael F. Castro Lang for appellant Hector Serrano-Acevedo. 

James L. Sultan, with whom Kerry A. Haberlin and Rankin & 

Sultan were on brief, for appellant Virgilio Diaz-Jimenez. 

 Nicholas W. Cannon, Assistant United States Attorney, with 

whom Rosa Emilia Rodríguez-Vélez, United States Attorney, and 

Mariana E. Bauzá-Almonte, Assistant United States Attorney, Chief, 

Appellate Division, were on brief, for appellee. 

June 13, 2018 
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LYNCH, Circuit Judge. We address in this case important 

questions of Fourth Amendment protections in a person's home. As 

we did in United States v. Delgado-Pérez, 867 F.3d 244 (1st Cir. 

2017), we conclude that the government overstepped the mark and 

that a motion to suppress the fruits of a warrantless search of a 

defendant's home in Puerto Rico should have been granted. 

Virgilio Diaz-Jimenez ("Diaz") and Hector SerranoAcevedo ("Serrano"), after a joint trial, were found guilty of 

armed bank robbery, in violation of 18 U.S.C. § 2113, and 

possession of a firearm during and in relation to a crime of 

violence, in violation of 18 U.S.C. § 924. Both defendants 

challenge their convictions, arguing that key portions of the 

evidence introduced against them were improperly admitted. 

Diaz argues that the government's warrantless search of 

his home violated his Fourth Amendment rights and that the district 

court erred by denying his motion to suppress the evidence 

uncovered during that search. Finding that the government's search 

does not fit within the protective sweep or voluntary consent 

exceptions under Fourth Amendment doctrine, the only even arguably 

relevant exceptions to the warrant requirement, we hold that the 

search of Diaz's home was unconstitutional. The evidence uncovered 

during that search was central to the prosecution's case at trial, 

rendering this error prejudicial. We vacate Diaz's conviction and 

remand for further proceedings consistent with this opinion. 
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Serrano, the other defendant, argues that several 

testimonial statements made during the trial, some of which 

referenced statements made by a confidential informant who did not 

testify, were impermissible hearsay testimony. If there was any 

error, it was harmless, so we affirm Serrano's conviction. 

I. Facts 

We review the district court's "legal conclusions 

involved in denying a motion to suppress the evidence de novo and 

its findings of fact for clear error." Delgado-Pérez, 867 F.3d at 

250 (quoting United States v. Marshall, 348 F.3d 281, 284 (1st 

Cir. 2003)). "On a motion to suppress evidence seized on the basis 

of a warrantless search, the presumption favors the defendant, and 

it is the government's burden to demonstrate the legitimacy of the 

search." Id. (quoting United States v. Winston, 444 F.3d 115, 

123-24 (1st Cir. 2006)). 

 Two armed men entered the Oriental Bank in San Lorenzo, 

Puerto Rico around 8:30 AM on June 17, 2013. The first gunman 

brandished his firearm and ordered the bank's security officer to 

"kneel down." The robbers told everyone in the bank to get on the 

ground. The second gunman then ordered the bank's employees to 

open the vault. After the bank employees turned over the money in 
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the vault area to the robbers, the gunmen left the bank and drove 

away in a white van. 

 The Puerto Rico Police Department provided a description 

of the van and its likely escape routes over the police radio. 

Officer Hector Ortíz-Alicia, hearing this, drove towards one of 

the possible escape routes. Once in the area, he saw a white van 

stopped by the side of the road. Ortíz-Alicia testified at trial 

that an armed individual got out of the van and, despite OrtízAlicia's orders to stop, fled into a grassy area nearby. Other 

testimony at the suppression hearing was that two people were seen 

leaving the van. 

 Ortíz-Alicia requested backup. Police searched the area 

with the help of a helicopter, but were unable to find the armed 

individual. The FBI and the Immigration and Customs Enforcement 

("ICE") Task Force reported to the scene. Agent Aristedes VázquezDíaz from the ICE Task Force reported to Agent Félix Rivera from 

the FBI that he had been contacted by an informant who had 

information about the robbery. 

 Shortly thereafter and at a different place, Agent 

Rivera and one or more ICE Task Force officers met with a 

confidential source who provided the nicknames -- El Domi and El 

Músico -- and cell phone numbers of two people who the source said 

were responsible for the robbery. The source stated that he had 

been in contact with the two robbers since the robbery and that 
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the robbers were hiding in nearby mountainous terrain and were 

waiting for the police helicopter to leave. The source stated 

that the robbers were expecting the source to pick them up. Agent 

Rivera had been planning to use this information to arrest the 

robbers at the pickup point. However, around 1:00 or 1:30 PM, the 

robbers notified the source that they had left their hiding place 

and no longer needed to be picked up. This information was passed 

on to law enforcement. 

 Law enforcement officers contacted the phone company in 

order to track the location of the robbers' two cell phones. One 

of the cell phones eventually became stationary in a rural, 

residential area in Barrio Borinquen. Between 3:30 and 4:30 PM, 

law enforcement officers traveled to that location, stopping at a 

crossroads close to the three-story home where they had been told 

the cell phone was located. The home was large and had a pool and 

a fence. Suspecting that the robbers were armed, Agent Rivera 

called in a SWAT team. 

 As the law enforcement officers waited at the crossroads 

for a SWAT team to arrive before approaching the residence, 

defendant Serrano drove through the crossroads in a blue Mitsubishi 

Nativa. Agent Vázquez-Díaz and Agent Julio Sánchez-Martínez, also 

from the ICE Task Force, recognized Serrano as El Músico, the 

person who the confidential informant had said was one of the 

robbers. Vázquez-Díaz had seen Serrano driving a blue Mitsubishi 
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Nativa before. Sánchez-Martínez and Vázquez-Díaz gestured to 

Serrano to stop and blocked the Nativa's path with their patrol 

car. 

 The agents got out of the patrol car, approached 

Serrano's car, and saw a gun in it. The agents twice told Serrano 

not to reach for the gun, Serrano eventually complied, and the 

agents arrested him. Serrano admitted that the firearm was his. 

The agents recovered a dark hat and a black jacket from the 

vehicle. FBI agents later recovered a pair of blue and black Nike 

tennis shoes from inside the car and a bag full of cash hidden in 

the car's air filter. After the arrest of Serrano, the monitored 

cell phone was still located at the three-story house. 

 The evidence at the suppression hearing about what 

happened thereafter at the house was based on the testimony of the 

FBI agent in charge, Agent Rivera, who was not actually at the 

home initially. Around thirty minutes after Serrano's arrest, the 

SWAT time arrived at the crossroads near the large three-story 

home where the cell phone was said to be located. While Agent 

Rivera waited behind, the SWAT team approached the home, knocked 

on the door, and heard a toilet flushing and people talking inside 

the home. The SWAT team opened the door and called to the people 

inside the home, but remained outside. Diaz's wife came out of 

the home first and was detained, and Diaz came out shortly 

thereafter. Diaz was immediately arrested and was at some point 
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handcuffed (the record does not reveal whether Diaz's wife was 

also handcuffed). SWAT team then, after Diaz was arrested outside, 

entered and did a sweep of the home. 

 During this sweep, the SWAT team "went to different 

places, and they saw money on top of the bed, they saw money inside 

the toilet." After the SWAT team had come outside following the 

search, they reported what they had seen to Agent Rivera, who by 

then had arrived. Agent Rivera then asked for Diaz's consent to 

conduct a search of his home. Diaz was arrested and in handcuffs 

at the time. Agent Rivera testified that Diaz consented verbally 

but refused to sign a form to that effect. The FBI then did a 

subsequent search of the house and recovered around $24,000 in 

cash and a box for a pistol. Diaz's wife consented to the search 

after it had occurred, and did so in writing. The cash found was 

bound with initialed bands, and bank tellers at the Oriental Bank 

later confirmed that their initials were on the bands. 

 Diaz filed a motion to suppress the evidence recovered 

during the warrantless search of his home. The magistrate judge 

held a hearing on the motion. Agent Rivera was the prosecution's 

only witness at that hearing. Agent Rivera did not testify that 

he was the one who ordered the SWAT team to perform the sweep, but 

he provided reasons for why he believed the search was justified. 

The prosecution primarily argued that the search was permissible 

because the officers were in "hot pursuit" of Diaz at the time. 
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It did not even attempt to justify the search as a protective sweep 

meant to protect the safety of the officers. 

 Diaz, in opposition, argued that there was no "hot 

pursuit" because the SWAT team's search was conducted more than 

eight hours after the robbery and, further, he had already been 

placed under arrest before the sweep. The magistrate judge 

recommended that the district court deny Diaz's motion, based on 

acceptance of the prosecution's hot pursuit theory. The district 

court adopted that recommendation. 

 Evidence obtained during the search of Diaz's home was 

used at trial by the prosecution. A jury found Diaz and Serrano 

guilty of armed bank robbery and use of a firearm in the commission 

of a federal felony. Diaz was sentenced to 192 months' 

imprisonment and five years' supervised release. Serrano was 

sentenced to 180 months' imprisonment and five years' supervised 

release. 

II. Merits 

A. Diaz 

 Diaz challenges the district court's denial of his 

motion to suppress the evidence recovered from his home, arguing 

that the search violated his Fourth Amendment rights and that the 

admission of the evidence recovered in that search was prejudicial. 

The prosecution, on appeal, attempts to justify the search under 

the protective sweep doctrine. We bypass the issue of whether the 
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prosecution waived its protective sweep exception argument because 

the argument fails on its merits. 

The Fourth Amendment forbids unreasonable searches and 

seizures, and a search of an individual's home "is generally not 

reasonable without a warrant issued on probable cause." Maryland 

v. Buie, 494 U.S. 325, 331 (1990). One exception to this rule is 

"a protective sweep conducted in conjunction with the arrest of an 

individual in his home."1 Winston, 444 F.3d at 118 (citing Buie, 

494 U.S. at 327). "A protective sweep is 'a quick and limited 

search of premises, incident to an arrest and conducted to protect 

the safety of police officers or others.'" Delgado-Pérez, 867 

F.3d at 251 (quoting Buie, 494 U.S. at 327). In order for a 

warrantless search to be a protective sweep, "there must be 

articulable facts which, taken together with the rational 

inferences from those facts, would warrant a reasonably prudent 

officer in believing that the area to be swept harbors an 

individual posing a danger to those on the arrest scene." Buie, 

494 U.S. at 334. 

 The prosecution argues that the search of Diaz's home 

was permissible because the officers had reason to believe that a 

person involved in the robbery was inside Diaz's home when they 

arrived and had remained inside the home both after the SWAT team 

 1 The government does not defend its hot pursuit theory on 

appeal. 
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breached the door and ordered everyone out and after Diaz and his 

wife had come outside and Diaz had been arrested. As Serrano and 

Diaz had already been detained at the time of the sweep and could 

not possibly have posed a threat, the government's argument depends 

on there being "articulable facts" supporting a reasonable 

inference that, at the time of the sweep, there was a third bank 

robber in the house who was armed and remained inside Diaz's home 

despite Diaz and his wife having come outside and been apprehended. 

Id. 

 The government does not provide any facts supporting its 

theory that a third person remained in the house after Diaz and 

his wife came out. Nor does it attempt to explain why it could 

not have gotten a warrant before entering the house. Agent Rivera 

admitted that they had received no information suggesting the 

existence of a third participant in the bank robbery. Indeed, the 

evidence known to the officers then was that there were two people 

who robbed the bank and then got away. Two people were seen 

getting into a van at the scene of the crime. An informant had 

told authorities that "two individuals known to him . . . were 

responsible for this bank robbery." (emphasis added). Agent 

Rivera stated at the suppression hearing that the information law 

enforcement had was that two people had been spotted parking the 

van by the side of the road several hours after the robbery and 

fleeing into the surrounding woods. Law enforcement had arrested 
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Serrano during a traffic stop and Diaz at his home shortly 

thereafter. That accounts for the two people seen during the 

robbery and leaving in the van, and abandoning the van later. This 

alone undercuts the theory that there was a third person in Diaz's 

house. Even if there had been a third robbery participant in the 

van when it left the bank, he had separated from Diaz and Serrano 

before the van stopped. There was no articulable basis to believe 

that he would be in Diaz's home. 

 Agent Rivera testified that because "as soon as the [two] 

individuals left [the bank], they went inside the van and left the 

location," he simply "assumed that there was a third waiting for 

them in the van." (emphasis added). This assumption was based on 

unfounded speculation, not "articulable facts" in the record. 

Delgado-Pérez, 867 F.3d at 251. 

 At oral argument, defense counsel asserted that 

"protective" sweeps are done as a "standard practice" in Puerto 

Rico regardless of the circumstances and that that may be what 

happened here. Neither explanation satisfies the constitutional 

requirements. 

 We reverse the district court's ruling denying Diaz's 

motion to suppress. The physical evidence recovered during the 

sweep, including the money from the bank, must be excluded as 

"unlawful fruit of the protective sweep." Id. at 257. 
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That does not end the matter. The prosecution argues 

that, even if the sweep was impermissible, Diaz's later consent to 

a search of his home -- while he was outside the home, under 

arrest, and in handcuffs and after the SWAT team had entered his 

home -- independently led to a constitutional search that recovered 

additional money inside Diaz's home.2 Given that the consent 

followed an illegal search, the evidence recovered in the consent 

search should still be suppressed if it "bear[s] a sufficiently 

close relationship to the underlying illegality."3 Delgado-Pérez, 

867 F.3d at 256 (quoting New York v. Harris, 495 U.S. 14, 19 

(1990)). This inquiry looks to factors including "temporal 

proximity, the presence of intervening circumstances, and the 

purpose and flagrancy of the official misconduct." Id. at 257 

(internal quotation marks omitted) (quoting Brown v. Illinois, 422 

U.S. 590, 603-04 (1975)). 

As a matter of law, once the search has been found 

illegal and a causal connection is evident, the government bears 

the burden of showing that Diaz's consent was sufficiently 

 2 The district court found that Diaz's wife's consent did 

not justify the warrantless search because she provided it after 

the second search had already begun. The government does not 

challenge that finding on appeal. 

3 Because we hold that Diaz's consent to the second search 

was tainted by the illegality of the SWAT team's sweep, we need 

not decide whether Diaz's consent was "knowingly, intelligently, 

and voluntarily given." United States v. Marshall, 348 F.3d 281, 

286 (1st Cir. 2003). 
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attenuated from the illegal search. See United States v. Kornegay, 

410 F.3d 89, 94 n.3 (1st Cir. 2005). The prosecution did not even 

attempt to make such a showing. Agent Rivera sought and received 

consent immediately after the SWAT team told him that they saw 

money in the house during the "protective" sweep and once Diaz was 

already in handcuffs. The record provides no indication that Diaz 

would have consented to the search if not for the unconstitutional 

sweep and what it uncovered. In response to this strong factual 

connection, the government "makes no argument as to why [Diaz's] 

consent was not the tainted fruit of the unlawful sweep." DelgadoPérez, 867 F.3d at 258. 

 Undaunted, the government next argues that any error is 

harmless because the "remaining evidence introduced at trial," 

including Diaz's former cellmate's testimony that Diaz made a 

jailhouse admission to his cellmate that he acted as a lookout 

during the robbery and the cell-site data showing the phone was 

located near the location of the robbery and in Diaz's home, 

"established that he participated in the robbery." Given the 

constitutional error in this case, we must remand for a new trial 

unless the error was "harmless beyond a reasonable doubt." United 

States v. Leon-Delfis, 203 F.3d 103, 112 (1st Cir. 2000) (quoting 

Milton v. Wainwright, 407 U.S. 371, 372 (1972)). 

 The evidence recovered from Diaz's home was central to 

the government's case, so the error was certainly not harmless 
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beyond a reasonable doubt. See id. (concluding that the admission 

of "highly probative" evidence "likely to be at the center of a 

jury's attention," which was obtained in violation of the 

defendant's constitutional rights and which should have been 

suppressed at trial, was not harmless beyond a reasonable doubt). 

The bands around the cash found in Diaz's home, which were 

initialed and later identified by Oriental Bank employees, 

directly linked Diaz to the robbery. The government referenced 

this evidence repeatedly throughout closing argument. The pistol 

case recovered from Diaz's home was also used to connect him to 

the robbery. 

 The government's other evidence of guilt is weak in 

comparison. Roberto Capo-Ortiz, Diaz's former cellmate, testified 

that Diaz admitted to him that he acted as a lookout during the 

robbery. There was no purported admission that Diaz was one of 

the robbers. Diaz argues that Capo-Ortiz's testimony was selfinterested and untrustworthy. Indeed, Capo-Ortiz is a convicted 

felon who testified in this case in the hope of having his twelveyear sentence reduced. The prosecution's cell-site evidence 

places cell phones registered to Diaz near the bank, in the woods 

near where the van was abandoned, and finally near his home. While 

that is relevant evidence, it is not so strong as to make a guilty 

verdict so likely as to render the admission of the evidence 

recovered from Diaz's home harmless. Given the centrality of the 
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money to the government's case at trial, we cannot find that the 

error was harmless beyond a reasonable doubt. 

B. Serrano 

 Serrano's only argument4 is that several testimonial 

statements made by Agent Sánchez-Martínez and Agent Vázquez-Díaz 

were improper hearsay. The most potentially damaging statement -- 

Vázquez-Díaz's testimony that an informant told him the names of 

the robbers -- was stricken from the record and was subject to a 

curative jury instruction. Serrano never requested more regarding 

the statement, so our review is for plain error. United States v. 

Colón-Díaz, 521 F.3d 29, 33 (1st Cir. 2008). "When a witness 

strays into forbidden territory, . . . strik[ing] the wayward 

remark and instruct[ing] the jury to disregard it" will usually 

"suffice to safeguard the aggrieved party's rights." United States 

v. Lee, 317 F.3d 26, 35 (1st Cir. 2003). Serrano, who falsely 

claims that this statement was admitted into evidence, provides no 

credible reason why the district court's remedy was plainly 

erroneous. 

 Serrano also challenges the admission of testimony from 

Roberto Capo-Ortiz that Diaz told Capo-Ortiz that Diaz and Serrano 

committed the robbery. Serrano argues that this is inadmissible 

 4 Serrano does not argue that, if the Diaz verdict is 

vacated, his must be as well, and we see no basis for such an 

argument. 
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hearsay because Diaz's statement was not self-inculpatory under 

Federal Rule of Evidence 804(b)(3). Yet Capo-Ortiz later testified 

that Serrano himself confessed. This means that Diaz's alleged 

statement to Capo-Ortiz that Serrano had participated in the 

robbery added little to the prosecution's case, making the 

admission of that statement from Diaz harmless. See United States 

v. Perkins, 926 F.2d 1271, 1280 (1st Cir. 1991) (citing United 

States v. Benavente-Gomez, 921 F.2d 378, 386 (1st Cir. 1990)). 

 We need not address whether the remaining statements 

were hearsay because any error was harmless. "The admission of 

improper testimony is harmless if it is 'highly probable that the 

error did not influence the verdict.'" United States v. FloresDe-Jesús, 569 F.3d 8, 27 (1st Cir. 2009) (quoting United States v. 

Casas, 356 F.3d 104, 121 (1st Cir. 2004)). The evidence against 

Serrano was overwhelming. He was arrested with a bag full of cash 

hidden in his car. His car contained a pair of black and blue 

Nike tennis shoes, and a witness at trial described the robber as 

wearing "Nike black and blue shoes." His car also contained a 

handgun. Given the strength of this and other evidence, it is 
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highly probable that the alleged errors Serrano identifies did not 

affect the outcome of the trial. 

III. Conclusion 

 We vacate Diaz's conviction and remand for further 

proceedings consistent with this opinion. We affirm Serrano's 

conviction.