A Grand Rapids man accused in the March shooting death of a young father carried out a “cold-blooded ambush’’ with an assault rifle, firing 31 rounds at his victim, a prosecutor told jurors Friday.

“All of the rounds are fired at one person,’’ Kent County Assistant Prosecutor Travis Earley told jurors during closing arguments Friday in the murder trial of Robert Bruce Lewis Hallman.

“Like a dog laying on the ground, he’s shot from behind,’’ Earley said. “Some of those had to have been shot into his body as he lay there on his face.’’

Stroy Pittman, 26, died from multiple gunshots inside Alger Meadows apartments on Ottillia Street at Nelson Avenue SE.

Hallman, 32, is charged with first-degree murder and two weapons offenses for the March 10 slaying. It was the city’s first homicide of 2016.

The trial before Kent County Circuit Court Judge Mark Trusock got underway Monday. A jury of six men and six women began deliberations late Friday afternoon.

Defense attorney Damian Nunzio concedes that Hallman was there, but says he had nothing to do with the murder. Hallman and Pittman got into an argument prior to the shooting and Hallman walked away, even after being punched in the arm, he told jurors.

Nunzio also questioned the truthfulness of prosecution witnesses.

“Don’t convict him on testimony from witnesses that are invoking the fifth amendment,’’ Nunzio told jurors. “You know, if you put enough circumstantial evidence together, everybody’s guilty.’’

Earley said .223-caliber shell casings found in the backyard of Hallman’s home on Temple Street SE matched evidence at the scene of the murder. Police also recovered from his home two 30-round magazines, one of which was empty, and a rifle case.

When he was questioned by police, Hallman said he had been home all night, but that was not the case, Earley told jurors.

Grand Rapids police were called to the apartment complex shortly after midnight to investigate a reported shooting. Witnesses said a lone suspect entered the building prior to the shooting and had fled by the time police arrived.

Pittman had been living at Alger Meadows for less than a year and worked at Building Maintenance Corp. in Grand Rapids less than two miles from his home.