Roger “Tom” Marmet (Family photo)

D.C. police on Friday arrested a suspect in the October killing of a 22-year-old man who authorities say was struck by what they believe was a stray bullet while sitting in his Jeep at a traffic light in Northeast Washington.

Roger Thomson Marmet, known as “Tom” to his family and friends, had just left his volunteer job helping recovering drug addicts at a job assistance center when he was caught in gunfire at Bladensburg Road and 17th Street NE, on the edge of the Trinidad neighborhood.

On Friday, D.C. Police Chief Peter Newsham announced that members of a regional fugitive task force had arrested Barry Marable, 22, of Northeast on a charge of first-degree murder while armed.

Marable’s initial appearance in D.C. Superior Court is scheduled for Saturday.

Newsham said at a news conference that Marmet was a young person “who had dedicated his life to helping the homeless . . . who was just on his way home.”

Newsham also highlighted an arrest made Monday in the 2016 fatal shooting of Ivy Tonett Smith, 39, who was at a bus stop and carrying her groceries when she, too, was struck by a stray bullet.

Smith was shot March 6, 2016, in the 2800 block of Alabama Avenue SE. Police charged Xavier Eugene Hamilton, 26, with second-degree murder. Newsham described Smith as a mother who worked for a property management company and as a barista at a coffeehouse.

Smith, too, Newsham said, “was an innocent bystander.”

“It’s senseless to see these kinds of murders happen in our city,” he said.

Marmet’s killing came amid a rising homicide count in the District, which as of Friday afternoon was at 159, a 39 percent increase over the same time last year, which ended with 116 killings.

Several homicide victims this year have been bystanders. A month before Marmet was killed, Wendy Martinez, 35, was fatally stabbed as she was on a run through Logan Circle in what police described as a random attack. A man was ar rested in that case. Over the summer, 10-year-old Makiyah Wilson was fatally struck by one of more than 70 bullets fired by four masked men in a courtyard in Northeast during what police suspect was a feud. Several suspects are under arrest.

Marmet left the So Others Might Eat center in the 4400 block of Benning Road NE about 6 p.m. Oct. 24. He was headed to a group dinner with other volunteers in a residence dubbed Gandhi House, about five miles away in Brookland. He was about halfway there when he reached Bladensburg and 17th, near the National Arboretum. He had joined the group’s year-long service program and was assigned to the center in the Lincoln Heights neighborhood in Northeast. He grew up in Chevy Chase and was the youngest of three.

Marmet’s father, Roger Marmet, who owns Roofers Union Restaurant in Adams Morgan, learned of the arrest while visiting Europe with his family. He said he has struggled to comprehend what happened.

“I think this doesn’t bring any sort of closure to us because we have a long road ahead, but it does explain some things,” Roger Marmet said. “If somebody is out there willing to shoot across traffic during rush hour on a busy road, we should hope they would be off the streets so this won’t happen to anybody else.”

Roger Marmet said he wants to help officials prevent more killings and stem the flow of firearms into the District. He said he doesn’t know the circumstances behind the shooting that killed his son, or even the suspect’s name, calling those details irrelevant.

“I”m glad the Wharf is doing well,” the father said. “I own a restaurant. But we’ve got to own the whole city. I didn’t have a sense of how bad things are, but now I do, and I want to be a part of making it better. . . . My son was a social worker serving the most vulnerable, the homeless, and yet he couldn’t drive across town without getting shot.”