On Monday, a Suffolk Superior Court jury convicted Joseph Cousin, 25, of second-degree murder for gunning down 10-year-old Trina Persad in 2002, according to the Suffolk District Attorney’s office. She was shot in a gang feud she had nothing to do with in Jermaine Goffigan Park - itself named for a young boy shot to death in a gang feud he had nothing to do with.

On Tuesday, Judge Nancy Staffier Holtz sentenced him to life in prison with the possibility of parole after 15 years, and consecutive terms of eight to 10 years on a motor vehicle conviction and 4 1/2 to five years on a firearms conviction.

“We hope this verdict provides Trina’s family with some satisfaction that justice has finally been done on her behalf,” District Attorney Dan Conley said after the verdict.

Prosecutors charge Cousin was a member of the MIC gang, named for its turf on Magnolia and Intervale streets and Columbia Road, and that he was gunning for members of the Big Head Boyz out of Brunswick, Creston, and Fayston streets, in retaliation for a shooting on their turf.

Prosecutors say Trina was at the park with her two younger siblings and an adult family friend - who tried to rush them out of the park when she saw men in a car start arguing with other men at a park basketball court.

The car, which authorities determined was stolen, circled the playground as the adult led the children to the street. Prosecutors say the window was rolled down, Cousin stuck the barrel of a shotgun out and opened fire - hitting Persad in the face and leaving her with fatal injuries.

Cousin went on trial in 2004 for her murder, but a mistrial was declared after prosecutors learned several jurors had lied about their criminal records. Fellow alleged gang member Marquis Nelson was found innocent by a jury also containing several members with criminal records.

It had taken until now to get Cousin a new trial in part because he appealed efforts all the way up to the Supreme Judicial Court, which ruled in 2007 he could be tried again.

Two of Cousin’s fellow gang members - and two members of the rival Big Head Boyz - testified against him.