Ray A. Young worked for the federal government for more than 30 years. He has fought throat cancer, losing his teeth and part of his jaw in the process. He has a college-age son and was seen as a friendly neighbor by those living in the tidy townhouses on Concerto Lane in the White Oak area of Montgomery County.

On Thursday, Young, 67, drove his Toyota Corolla to the U.S. Post Office three miles away in Colesville. He waited with the rest of the afternoon crowd. Then he thought he saw a man cutting in line.

In fact, the man had been directed away from the counter to finish his paperwork, then had been motioned back by a postal worker, according to Montgomery County police.

Precisely what happened next in the post office’s vestibule remains unclear. But the man told police that Young came up to complain, then started to yell and argue with him before pulling a four-inch knife out of his pocket and stabbing him over and over.

Witnesses watched as the men fought and a postal worker pepper-sprayed them both, authorities said.

Young then went to retrieve some sort of pole from his trunk — one witness thought it looked like a baseball bat — and headed back toward the man, police said. But bystanders shouted that they had called police, and Young turned around and drove away. Police detained him a short time later in a traffic stop.

Authorities charged Young with attempted murder, and on Friday he appeared by closed-circuit television in a Rockville courtroom, where a judge held him on a $500,000 bond. Young’s son wept afterward just outside the courtroom doors.

Police say Young stabbed the victim several times, wounding him in the chest, forearm, biceps, and shoulder. The man, who had worked at the District’s Department of Transportation, was hospitalized with serious but not life-threatening injuries.

Police said that at the post office, Young walked out to the vestibule, waited for the victim, then attacked him.

But Young gave police a different account.

“I was fighting with a guy. He cut the line and I said something to him,” Young said, according to an officer’s account. “We started tussling. He punched me and hit me with his head,” Young said, then demonstrated by motioning as if he was head-butting someone.

According to the police account, Young continued: “I was defending myself. His wife or someone pepper-sprayed me. Maybe I should have stayed home. I’m too old for this stuff.”

Young worked at the Department of Labor, according to his lawyer, Gary Courtois, and served 37 years as a federal government employee. He’s active in his church and community and has no history of violence, Courtois said.

“He’s as stable a citizen as you could ask for,” Courtois said. “Something must have happened in that parking lot. He must have felt threatened.”

Mary Anne Darling said Young has been friendly and helpful as a neighbor.

“We have lived next door to him for more than 10 years, and I’ve never seen him be aggressive or volatile in any way,” said Darling, a special education teacher. Young is “the kind of neighbor who checked your mail when you were away and checked your house while you were on vacation.”

Darling said she hopes the victim recovers, and “I hope Ray gets the help it seems like he might need.”

Another neighbor said he had walked a letter over to Young a few days ago. “He seemed just like a standard, normal dude. He was always very polite to me,” said Evan Schluederberg, who works in property management.

Young’s brother, who would not give his name, declined to comment and asked that family members not be bothered.

The victim’s family also declined comment.

Jennifer Jenkins contributed to this report.