Gov. Murphy on Monday condemned a weekend shooting at an arts festival in Trenton that injured 22 people and left one of the suspected gunmen dead and he vowed to bring those responsible for "the lawlessness" to justice.

Murphy praised law enforcement officers for their response when gunfire erupted early Sunday morning at the Art All Night event at the Roebling Wire Works warehouse.

Authorities said Monday that several officers fired their weapons during the encounter with at least three suspects. It was unclear whether the wounded were struck by police or the gunmen.

A spokeswoman for Mercer County Prosecutor Angelo Onofri could not say how many officers were involved or how many rounds were fired. Because the shooting resulted in a fatality, the officers involved have been placed on administrative leave pending an investigation, Casey DeBlasio said.

"It's more than one," she said. "It's multiple."

Authorities say the shooting began amid escalating altercations among visitors in what may have been a gang-related dispute. Two men started shooting at about 2:45 a.m., police said. There was gunfire inside and outside the venue on the 600 block of South Clinton Avenue, they said.

About 1,000 people were at the event when the shooting began, triggering a stampede. A 13-year-old boy was among the injured. Authorities said 17 people were shot and many others were injured in the chaos and panic that followed.

"It could have been a lot worse and even more deadly," Murphy said at a Statehouse news conference.

Trenton Police Director Ernest Parrey Jr. said in an interview Monday that the arts event had its own security and had also hired some police officers. Other units were nearby, Parrey said, estimating that there were "close to 40 officers in the immediate area of the event" before the shooting began.

At least six people who sustained gunshot wounds or were injured during the stampede, including two suspects, remained hospitalized Monday. A dozen others were released.

The shooting remained under investigation as questions emerged about the background of Tahaij Wells, 32, identified as one of the gunmen. He was shot to death by police, authorities said. The results of an autopsy conducted Monday were not immediately available, DeBlasio said. Wells had been on parole since February after serving 14 years in prison for a fatal shooting he committed when he was 17.

Another suspect, Amir Armstrong, 23, remained in critical but stable condition with unspecified gunshot injuries, DeBlasio said. Armstrong was charged with weapons offenses, including having a handgun with an extended capacity magazine. Armstrong, of North Trenton, has no felony convictions.

A woman who answered the door at Armstrong's home and said she was his sister, declined to comment. She said the family is focusing on her brother's medical care.

A third suspect was hospitalized in stable condition with gunshot wounds, DeBlasio said. He has not been charged and his name has not been released.

"They're still obviously investigating," she said. "He's a suspect."

Wells pleaded guilty to aggravated manslaughter in 2004, admitting that he killed a man in an argument over a woman. New Jersey State Police identified Wells as a member of the 93 Gangsters' Bloods gang. After his conviction, Wells spent 12 years in protective custody, which effectively kept him in solitary confinement. Prison officials said this was to keep him safe because the shooting he committed was an "unauthorized killing" of a fellow gang member. State prison officials said they believed that Wells could be killed in prison in retaliation.

Months before Wells' February release, a federal judge granted a request from his lawyer that he be allowed to join the general prison population. His lawyer successfully argued that the danger of any threat had passed and said Wells should be housed with others and allowed to socialize in preparation for leaving prison.

While behind bars, Wells remained involved with the Bloods. In 2010, he pleaded guilty to racketeering charges stemming from his involvement in helping run the gang from prison. He was sentenced to six years in prison, but that term was concurrent with his sentence for the killing.

DeBlasio said investigators believe Sunday's dispute was between what she described as neighborhood street gangs. She said she had no information on Wells' gang affiliation.

On Monday afternoon, about a half-dozen people were gathered on the porch outside Wells' home, and two small children played on the sidewalk. His mother and a sister declined comment.

"He was a good dude," said Peter Williams, a friend. "It wasn't the way they made him out to be in the news."

At the scene of the shooting Monday, a large area around the venue and the streets around the warehouse were blocked off by yellow crime-scene tape and police vehicles. The building appeared empty with banners for the Art All Night event still hanging. The sidewalk and picnic tables outside were littered with trash.

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At a crowded news conference, Murphy agreed with remarks by Mayor-elect Reed Gusciora that the shooting appeared to stem from a turf war between rival gangs. Despite the weekend melee, the governor said he would like to see the arts festival continue and said the city needs more events like it to keep its young people out of trouble.

"While the headlines shocked all of New Jersey, gang violence is an all-too-stark reality on too many streets in the city," the governor said. "I'm not going to turn my back on Trenton."

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Onofri, the county prosecutor, said the shooting remains under investigation, including an examination of the extent of the officers' involvement in any shootings. "Multiple" guns were recovered at the festival scene, he said, and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives was at the site to tally up spent casings.

The prosecutor's office is reviewing video footage and interviewing witnesses to the shooting and investigating whether the use of deadly force by police was justified, DeBlasio said.

Onofri will attend a community meeting at 10 a.m. Tuesday at Friendship Baptist Church, 111 Perry St., DeBlasio said. He was invited by John Taylor, the church's pastor, who will address recent violence in Trenton along with the Capital City Community Coalition, she said.

The weekend violence marred an event, in its 12th year, that aimed to attract 30,000 visitors to experience visual artists, short films and a diverse range of about 60 live music groups in a 24-hour marathon. It was held at the site of a former factory that built or erected cables for the Brooklyn Bridge, the George Washington Bridge and the Golden Gate Bridge. The remainder of the festival, which was scheduled to run until Sunday afternoon, was canceled.

ArtPride New Jersey, which calls itself "a voice for New Jersey's arts industry," released a statement from its president and CEO, Adam Perle, in support of Artworks, which hosts Art All Night.

"We have no doubt they will tap the power of the arts to bring people together now, as they have in the past, through the irrepressible work of the region's brave and resilient cultural community," Perle said.

Gusciora, the mayor-elect, said the Arts All Night event should continue  – but with more security. Officials had discussed increasing security this year, but the city did not recommend the use of metal detectors.

"What I think the city needs to do in the future is partner with the nonprofits to make sure they truly have enough security personnel in place," he said in an interview Monday.  "And we'll certainly be working with them in the future to make sure that it is a safe and fun and rewarding experience."

Staff writer Max Cohen contributed to this article.