A Domino’s driver delivering a pizza to a Seat Pleasant apartment complex and a man who had pulled into a Capitol Heights gas station after a night out were shot to death in separate incidents in Prince George’s County late Sunday night and early Monday morning, authorities said.

The slayings brought the county’s homicide total to four since Thursday.

The Domino’s case was of particular concern to Prince George’s detectives. Police said it appears that Domino’s driver Paul Jason Bennett, 38, of the District, was just doing his job when he was shot to death in a possible robbery.

The gas station shooting also had detectives working through the night. Police said they are exploring whether that incident might have stemmed from an earlier altercation at a nearby nightclub.

The homicides bring the county’s total for the year, including killings deemed justified by police, to 28. At this time last year, police had recorded 21 killings.

Police first learned of the Domino’s case at about 8:30 p.m. Sunday, when someone called 911 to report a man on the ground in the 6800 block of Seat Pleasant Drive. Officers arrived to find Bennett suffering from a gunshot wound. He was taken to a hospital, where he was later pronounced dead.

Police spokesmen said the case appears to be a robbery in which the suspects had placed a pizza order. Detectives are still investigating a precise motive.

Pearl Bennett, 72, Paul Bennett’s mother, she was expecting her son home between 12:30 and 1 a.m. Monday when she saw on the 11 p.m. television news that a Domino’s driver from the Central Avenue store had been killed.

She said she told her husband, “You know Paul work at that same place?” At 1:30 a.m., Bennett said, detectives knocked on her door.

“I said . . . ‘Is it my son? Is it my son?’ ” Bennett said.

Bennett said detectives and others told her that her son was called to the area where he was killed, and the suspects could not have taken more than $13 and pizza from him.

“The detectives told me he was delivering pizza, somebody called to order pizza, and then he delivered it, and then they killed him,” Bennett said. “Terrible, terrible, terrible.”

Bennett said her son was a “very hard worker” and was planning a first birthday party for his son next month. He had worked at Domino’s since 2008, she said.

Just after 3 a.m. Monday, police were called to another shooting at a Shell gas station in the 8300 block of Central Avenue, authorities said. They arrived to find Brian Vincent Cooper, 20, of the District suffering from a gunshot wound. He was taken to a hospital, where he was pronounced dead, authorities said.

Cpl. Henry Tippett, a police spokesman, said detectives think Cooper had been inside the nearby MSG nightclub before the shooting occurred, and they were exploring whether the shooting stemmed from an incident there.

Eric Pickens, an assistant manager at MSG, said the club had hosted a cabaret Sunday night that let out at 2:45 a.m., but the only altercation involved females. He said officers who work security for the club responded to the shooting scene, and they did not recognize the victim as a patron.

“Usually we’re pretty quick to get blamed,” Pickens said. “But with the timeline that it was and with us having no male incidents, I feel comfortable saying that was an unfortunate, random [incident].”

Efforts to reach Cooper’s relatives were unsuccessful.

Staff researcher Madonna A. Lebling contributed to this report.