Correction: One reference in an earlier version of this story to Ronald Lee Ragland’s conviction for the second-degree murder of Robert Mitchell Sr. substituted Ragland’s last name for Mitchell’s. This version has been corrected.

A Hyattsville man who fatally shot someone during a robbery and a Brandywine man who gunned down his neighbor after years of disputes were convicted of murder last week in separate trials, Prince George’s County authorities said Wednesday.

Prosecutors said 22-year-old Dominic Givens, of Hyattsville, was convicted of first-degree murder and related counts in the 2011 killing of 30-year-old Marvin D. Tomlinson, and 56-year-old Ronald Lee Ragland, of Brandywine, was convicted of second-degree murder in the shooting death of 53-year-old Robert Mitchell Sr.

Tomlinson, prosecutors said, was shot during a robbery, Mitchell as a result of an ongoing dispute with a neighbor.

In Givens’s case, prosecutors said they presented evidence that the 22-year-old was with three others who tried to rob Tomlinson and a group of teenagers in November 2011 near an apartment playground on County Road in District Heights. Tomlinson, prosecutors said, wrestled the gun away from his attackers and yelled for the teenagers to run, but they soon got it back and fatally shot him.

Givens is scheduled to be sentenced next month, and two of the others in his group are awaiting trial. A fourth man initially charged in the slaying and released on bond was later fatally shot, prosecutors said

Ragland’s case was quite different. Prosecutors said the Brandywine man had “years of ongoing disputes” with his neighbors, the Mitchells, and in May 2010, called one of them, 18-year-old Robert Mitchell III, into the street for a fight. Ragland shot Mitchell III in the hip, prosecutors said, then shot his father, Robert Mitchell Sr., twice at close range as he sat in his car.

After the shooting, prosecutors said, Ragland put an inoperable gun in Mitchell Sr.’s lap. He had initially claimed he shot in self defense, but that account was contradicted by Mitchell III, who survived, and other evidence, prosecutors said.

Ragland is scheduled to be sentenced in May, prosecutors said.