The family of slain mechanic Charles Cantave watched through tears today as one of his killers pleaded guilty to murdering him after a small claims court hearing over auto parts, Suffolk County District Attorney Daniel F. Conley said.

CORNELIUS EVANS (D.O.B. 6/19/75) of Dorchester pleaded guilty to second-degree murder this afternoon for his role in Cantave’s March 29, 2010, shooting death a block and a half from Dorchester District Court. Suffolk Superior Court Judge Frank Gaziano imposed the mandatory sentence for that crime, life in prison with the possibility of parole after 15 years.

Evans’ co-defendant, MARIO BURNS (D.O.B. 10/5/72), is expected to face trial next year for first-degree murder, the offense for which Evans was initially indicted.

Cantave’s sister, Maria Duverneau, addressed the court prior to sentencing, recalling the murdered Hyde Park resident as “a sunshine guy [who] brought light where there was darkness.”

Cantave, she said, managed the Brockton auto body shop owned by their parents and had “a passion for cars ever since he was young.”

On the day he was murdered, Cantave was in court for a civil action brought against him by Burns’ wife. Evans admitted to waiting outside the courthouse in their Chevrolet Suburban. After the hearing, prosecutors say, Burns and his wife entered the vehicle. Moments later, they saw Cantave cross the street in front of them on the way to his own car.

Burns allegedly pointed Cantave out to Evans, who admitted leaving the car, running over to Cantave, and shooting him dead before running back to the Burns’ vehicle.

Witnesses provided Boston Police with Burns’ license plate number. Burns was arrested April 8 and charged with being an accessory after the fact to Cantave’s murder; on April 13, as a result of evidence developed in the Suffolk County Grand Jury, both he and Evans were charged with murder.

Katherine Moran was the DA’s victim-witness advocate on the case. Evans was represented by attorney Matthew Feinberg. Burns is represented by attorney Bernard Grossberg and is expected to face trial on Feb. 2.