While police continued to investigate a shooting at an Old Port recording studio in which a 19-year-old Scarborough man was killed, a vigil for the teen Tuesday night included at least two young men carrying handguns and talk of street retaliation.

Police believe more than one person was responsible for the double shooting late Monday.

Treyjon Arsenault was pronounced dead at Maine Medical Center early Tuesday, hours after he was shot inside the Da Block Records Inc. recording studio at 26 Market St., acting Portland Police Chief Vern Malloch said at a news conference.

A 20-year-old Portland man shot in the same incident has not been identified and is expected to make a full recovery, Malloch said. Police have interviewed him, but they would not disclose any information he may have provided about the shooting.

Police have not identified a motive, but Malloch said the victims were likely acquainted with their assailants. Police are asking the public for any information or tips that could lead to the capture of the shooter or shooters.

On Tuesday night, more than 100 people attended a candlelight vigil in memory of Arsenault in downtown Westbrook. The crowd, made up mostly of Arsenault’s friends and acquaintances about his age, lit candles on a public basketball court off Main Street where Arsenault was a regular. Those who attended grieved in different ways, some in disbelief that a polite, thoughtful young man was gone, and others reacted with hostility.

Some hugged, some wiped tears from their eyes and others talked of street retaliation, saying they know who killed Arsenault but they didn’t want to cooperate with the police.

Some young men at the vigil openly carried handguns in holsters at their hips. Westbrook police officers questioned the men with guns, acknowledging their rights under Maine law to carry firearms, and let them stay within the crowd.

Two of Arsenault’s friends who were not carrying guns, 21-year-old Jacorey Monteiro and 19-year-old Tim Javett, said they had heard who killed their friend, but wouldn’t repeat any names.

“The people who did it, they’re serious. They’re no one to (expletive) with,” said Monteiro, who had met Arsenault recently and became friends with him.

Javett said either police will arrest the killers soon, or he’s heard some of Arsenault’s friends will take matters into their own hands.

“Pretty much everyone knows what happened,” Javett said. “I think the Greater Portland area is at a breaking point.”

Police say there were seven to 11 people at the studio, which covers much of the third floor of the brick building at the corner of Fore and Market streets. Two suspects were seen running up Market Street toward Milk Street right after the shooting. Police said they will be analyzing security video from nearby businesses to try to identify the gunmen.

“Anyone who might have any information … anyone who might have been there, we really would like to speak with them as soon as possible,” Malloch said. “We believe the parties involved are known to one another.”

Asked if investigators had a suspect, Malloch declined to comment. Police early on called in the Attorney General’s Office, which prosecutes murders in Maine.

Arsenault graduated in 2014 from Westbrook High School, where he played football, hockey and baseball.

Westbrook High Principal Jon Ross said the mood at the school was somber Tuesday. Ross said Arsenault had a “big, positive personality” that resonated with classmates and faculty alike.

“Nobody saw this coming,” he said. “We have our crisis team in place so people can come in and talk if they need to.”

Word of the impromptu vigil spread quickly via Facebook and Twitter. The man who organized the event, Nicholai Kotsimpulos, said he had known Arsenault since childhood and thought his friend would have appreciated the large turnout.

“I’ve known him since we were little,” Kotsimpulos said. “He’s a good kid. He was just hanging out with the wrong crowd, and he started to change. I told him not to hang out with those kids.”

Some people in the crowd were hostile toward members of the media who came to the vigil, telling them that they weren’t welcome and should leave. But Kotsimpulos disagreed, welcomed the media and spoke for television cameras describing how he heard of Arsenault’s death.

“My friends called me and said, ‘Trey got shot.’ And I didn’t believe it, so I called his mom, and she was just crying,” Kotsimpulos said.

Arsenault had no criminal record, according to a search of state records.

Malloch was unaware of any calls for police service to the recording studio.

Ron Hargrove, the studio’s owner, said he was not in the building when the shootings occurred and he has tried to be helpful to police in their investigation.

“I’ve been there five years, there’s never been a fight there,” Hargrove said in a telephone interview Tuesday. “Everybody will tell you, the only thing that goes down there is music.”

He was upfront with them about his past, which includes a 2013 misdemeanor drug conviction, for which he served 60 days, according to state records. Police said they have no reason to believe drugs were involved in the shooting.

Witnesses at the shooting scene reported hearing several shots in two bursts.

Officers quickly descended on Market Street, locking down several blocks around the Market Street address between Middle and Fore streets.

Officers were on high alert immediately after the gunfire, with assault-style rifles and shotguns at the ready.

Raffi Emslie, who works at a second-floor billiards hall on Fore Street near the recording studio, said he saw a wounded man being carried by four police officers down Market Street toward Commercial Street. Emslie said the man appeared “lifeless.”

“There was a dude who I think was dead,” Emslie said. “He was bleeding from his stomach.”

Police detained a group of men near the scene, restraining some with handcuffs. Malloch said that is not unusual when police arrive at a violent crime scene as they try to determine who was involved.

One man was arrested at Fore and Market streets and charged with obstructing government administration, resisting arrest and carrying a concealed weapon, but he was not implicated in the shooting.

Police have denied that a third man at the studio was stabbed in Monday’s incident. But many people at the vigil said a man in the crowd, whom they identified as Jeffrey Silvia, was stabbed at the studio. Silvia stood at the center of a throng of young men at the edge of the basketball court, with a bandage and brace on his hand where people said he was stabbed.

Every time a member of the media approached Silvia, the men in his group stepped forward and said he didn’t want to talk and warned journalists to stay away.

Hargrove also said he had been told that someone had been stabbed at the studio. He also said that a drug raid Tuesday morning at house in East Deering near the Presumpscot Elementary School was connected to the shooting at Da Block Records. Police denied any connection and said undercover agents had purchased crack cocaine from Kerwin Lamour over the past month. They seized two handguns and ammunition during the raid.

Portland’s last murder was in November 2014 and the one before that was two years earlier, Malloch said.

“We just want to stress that Portland is a safe city, but like any small city, there are going to be incidents of violence,” Malloch said.

Portland averaged 2.7 murders per year from 2003 to 2012, or roughly 2 murders per 100,000 residents annually, according to City-data.com. That’s slightly more than one-third the national average of 4.7 murders per 100,000 residents annually. In the broader category of violent crimes (murder, rape, assault and robbery), Portland had 2.8 incidents per 1,000 population in 2013 versus a national median of 3.8, according to FBI statistics.

Malloch said the violent crime rate citywide has gone down consistently in recent years. He was unable to provide statistics on violent crime specifically in the Old Port without consulting with the department crime analyst.

Staff writers David Hench, Scott Dolan, Eric Russell and Dennis Hoey contributed to this report.