Dave French, 44, will be running in this year's Marine Corps Marathon in memory of Navy Yard shooting victim Martin Bodrog. (Matt McClain/The Washington Post)

Late into the evening of Sept. 16, Dave French waited for his neighbor to pull into the driveway on Paul Revere Court in Annandale. French had lived next door to Marty Bodrog for more than a decade in the quiet suburban cul-de-sac, and there were memories here. Maybe the best was when French’s young son was playing hockey in the street with his friends, and Bodrog came out with his own gear to join them.

In the hours after the Navy Yard shootings, this was where French desperately wanted his neighbor to return. But Bodrog didn’t come back; at around 11 p.m.. French learned he was one of the 12 people killed in the massacre.

The next day, French returned to work as director of IT operations at PBS in Arlington. Shaken and struggling to focus throughout the morning, he changed out of his business attire during his lunch hour and went for a run on the Mount Vernon Trail near Crystal City.

French has been an avid runner for nearly two decades, with just one condition: He nearly always runs alone. Now the thought crept into his mind: What if he had asked his neighbor, just once, to go running with him?

“I think anytime something like this happens to somebody, it does make you reevaluate your priorities and how you spend your time,” French said. “You just don’t think that when somebody leaves for work in the morning, you might not see them that evening.”

Map of 38th Marine Corps Marathon route. Rolling road closures will be in effect along the course from 4 a.m. to 5:30 p.m.

Sunday’s Marine Corps Marathon likely will be the most important race French has run. He has been training for the event since the summer, but only in the last six weeks has his approach intensified. He will be among 30,000 runners who will weave through the grueling course in Arlington County and the District, the first race in a long time French will not be running alone. He will be running with the memory of Bodrog.

“It just made sense to me to use that time to honor Marty,” French said.

He will run for the times Bodrog took care of his son, sending him back with a popsicle after receiving help with yard work. He will run for all the times Bodrog sat on his back deck, watching his beloved Boston Bruins; French always knew the outcome by his groans or cheers. He will run for the last time he spoke to Bodrog, the weekend before the shootings. The men were tending their lawns, and French was embarrassed by weeds that hadn’t been pulled. Bodrog laughed it off and told him not to worry about it. That was Marty, French said.

A week later, French wanted a way to honor Bodrog’s memory, so he reached out to the Marine Corps Marathon officials about making it official. It was one of the ways French could cope, according to his wife, Melissa.

“I think about it at least every day. There’s always something that comes up that makes us think about it,” she said. “I think that’s the only word for it: completely unbelievable. There’s no sense of it.”

French, 44, never envisioned running would take him on this kind of path, especially considering he started jogging only after college at Virginia Tech to stay in shape. Gradually, the sport became his release after the family settled into the Washington area in 1992. He took on 10-kilometer races. He completed half-marathons. Eventually, he ran in an ultra-marathon in Kansas at the age of 40. And even though he had developed an independent identity as a runner, he continued to contribute advice and route ideas with a small circle of people at work, some of whom will be running Sunday.

“He’s very active,” said PBS co-worker Marcia Apperson, who will also run in Sunday’s race. “It’s been months that we’ve been training, and he’s kind of taken a leadership role. Not that we run together, but he sends us e-mails every so often with tips or advice. . . . He’s been a big motivator during this whole process.”

30,000 runners will make their way to the start line for this weekend's Marine Corps Marathon in Washington, D.C. Race Director Rick Nealis joins Nia-Malika Henderson to talk about keeping the event safe and the increasing popularity of the long distance run. Plus, a local runner shares her story of running over 1,700 miles all over the world. (The Washington Post)

But many of the best runs for French have come when nobody is watching; those runs when he is able find an emotional release during his lunch hour at PBS or when he is in a bad mood at home. Physically he’s alone. But French said he has run in races for the memory of his best childhood friend, who died of colon cancer six years ago. He has run for his brother, who is fighting lung cancer, and his father, who has endured both prostate and skin cancer.

On Sunday, he will set out for Bodrog. French will take about four hours to complete the race, which will be painful and emotional in equal measure. It will be the run he and his neighbor never got to go on.

“When you’re running, you kind of leave anything else behind,” French said. “Some people say you can’t run from your problems, but I think sometimes running helps you leave them behind for a little while, at least.”