One of the gunmen accused in shootings that left one man dead and another injured in an Old Port recording studio last year pleaded guilty Thursday to a felony assault charge for wounding the man who survived.

Now that Johnny Ouch, 21, of Westbrook, has pleaded guilty, prosecutors may call on him to testify against his co-defendant, Gang Deng Majok, who they say fired the shots that killed 19-year-old Treyjon Arsenault.

Ouch admitted at the plea hearing before Justice Andrew Horton in the Cumberland County Courthouse in Portland that he shot his longtime rival, 22-year-old Mohamed Ali, inside Da Block Studios Inc. on May 25, 2015.

In exchange for Ouch’s plea to a charge of elevated aggravated assault, prosecutors agreed to dismiss a count of murder against him.

The terms of the plea agreement cap Ouch’s maximum sentence at 16 years. The judge did not immediately sentence Ouch, and no sentencing date has been set.

Ouch said little at the hearing other than to answer mostly yes or no to questions posed by the judge, and to enter his guilty plea. He stood between his attorneys, Amy Fairfield and Kevin Moynihan, and did not address members of Arsenault’s family or his own family, who were both in the courtroom.

Majok’s trial is scheduled to begin Sept. 12. He has pleaded not guilty to charges of murder and elevated aggravated assault.

Deputy Attorney General Lisa Marchese said both Ouch and Majok were suspects from early on in the shooting.

FIREARMS HAVE NOT BEEN RECOVERED

The conflict started as a fight inside the independent recording studio at Market and Fore streets, when Ouch and Ali encountered each other inside and resumed an old rivalry. Police have said they were among seven to 11 people in the studio on the building’s third floor when the shooting broke out.

“Their problems dated back to high school,” Marchese said of Ouch and Ali.

The space was crowded, and Ouch drew a .380 caliber pistol and fired, although he contends he didn’t mean to shoot anyone, Marchese said. His shot hit Ali, who was hospitalized afterward and has since recovered.

Then Majok allegedly fired multiple shots from a 9 mm pistol, striking Arsenault in the abdomen, she said.

Witnesses identified Ouch by name and picked his photo from a lineup. Witnesses also identified Majok by his nickname, Bang Bang, Marchese said.

“None of the firearms in this case have been recovered,” Marchese said. But she said witnesses have told police that Majok’s gun was thrown into the Saco River and Ouch’s was thrown into the water off Falmouth.

Fairfield, Ouch’s defense attorney, described the conflict inside the studio as a “melee.”

“This was a very crowded room,” she said. “The use of a gun in that room was not justified given the type of fight that had broken out.”

Outside the courtroom after the hearing, Fairfield said Ouch had been charged with murder under the “accomplice liability theory,” and that authorities never believed he had shot Arsenault.

“In the context of being charged with murder, this plea is in his best interest, and there is an opportunity for an excellent outcome in the back end,” Fairfield said.

‘IT JUST SEEMS SO SENSELESS’

Ouch’s mother, siblings and girlfriend declined to comment as they left the courthouse.

Arsenault’s mother, Nancy Laxson, said sitting through the plea hearing was particularly difficult for her and that she anticipated that Majok’s trial would be even harder.

“I’m having a hard time,” Laxson said. “It just seems so senseless. It should never have happened.”

Her son was a bystander in the shooting and had no prior conflicts with Ouch or Majok. Arsenault was a graduate of Westbrook High School, where he was a co-captain of the football team.

If Majok is convicted, he faces a minimum of 25 years and up to life in prison on the murder charge. Elevated aggravated assault is a Class A felony punishable by up to 30 years in prison.

Ouch has no adult criminal record, and his only publicly available conviction is for criminal mischief as a juvenile in 2010.

Majok has a lengthy criminal history, although it’s unclear whether he has spent significant time in prison.