Family members can only assume that Harold T. Detter was on his way home from work Tuesday, waiting in the bus bay of the Southern Avenue Metro station after another long day. Not having a car, the 43-year-old IT worker used Metrorail and bus service to get to and from his job, family members said.

But Detter never made it to his Oxon Hill townhouse. As those at the Metro station watched, a stocky 32-year-old approached him about 9:30 p.m. and fatally shot him in the upper body, police said. The gunman did not say a word and did not rob Detter, police said.

“My son — all he did was work,” said Vivian Detter, hugging other crying relatives outside her home Wednesday. “I couldn’t fathom anybody taking his life.”

Prince George’s County police on Wednesday charged Norman M. Bonds, who lives on Dixon Street not far from the Metro station, with first-degree murder. Maj. Michael Straughan, who commands the department’s criminal-investigations division, said that information from several witnesses helped detectives identify Bonds as the sole suspect.

Straughan said that both Bonds and Detter frequented the Metro station but that detectives were still working to determine what prompted the shooting and whether the men knew each other. No words seemed to be exchanged before the shooting, police officials said, and there was no evidence of a robbery.

“This was a direct walk-up and shooting,” Straughan said.

Detter’s family members said they had never seen or heard of Bonds — who has a lengthy criminal record, including convictions on drug, assault and trespassing charges — and they doubted that Detter knew him. Detter was a professional who spent 12-hour days at various IT jobs, the family members said. He had worked providing customer support for a home-security company based in Virginia and recently switched to another job family members said they knew little about.

In his spare time, Detter enjoyed watching horror movies and texting with his daughter, 9-year-old Brianna Detter, his family said.

“He was a jokester. He kept everybody laughing,” said his sister, Laurenda Detter, 46. “My brother didn’t deserve this.”

Family members had limited contact with Detter in recent months because of his hectic work schedule, they said.

Laurenda Detter said that in late April, she grew so worried about her brother working so much that she set up a “stakeout” at his house. She said he looked to have lost weight and complained of having been sick and working a lot. “I’m like, ‘Yeah, but don’t kill yourself,’ ” she said.

Family members said that as far as they knew, Detter usually took the D-12 bus home from the Suitland Metro station. They said they were unsure why he was at the Southern Avenue station Tuesday but believe that he was returning from work.

As detectives ushered Bonds out of police headquarters Wednesday and into a car, the suspect did not respond to reporters shouting questions at him. A woman at his home on Dixon Street — who identified herself as his grandmother but declined to provide her name — said she was unaware of the charges against her grandson. She said she did not recognize the name Harold Detter.

“I don’t know nothing about it,” she said.

Staff researcher Magda Jean-Louis contributed to this report.