A man handing out free Express newspapers at a Metro station in Maryland stabbed a commuter after arguing with him, Metro officials say.

Daniel Richard Brown, 50, was being sought by police Thursday night on suspicion of attempted murder, Metro Transit Police said. He is 6 foot, weighs 220 pounds and lives in Temple Hills, Maryland, police said. Anyone who sees him is asked to call police immediately and take no other action.

The newspaper vendor -- a contractor with Express' parent company, The Washington Post -- argued with a man about 9 a.m. at the Addison Road-Seat Pleasant station in Capitol Heights, Maryland, Metro spokesman Dan Stessel said.

"They get into an altercation that escalates to physical, and on the sidewalk ... here, the suspect tackled the victim and ending up stabbing him," he said.

The attacker surrounded by witnesses and caught on multiple high-definition surveillance cameras then ran away, Stessel said.

The victim, a 24-year-old man, was taken to a hospital with serious injuries. He was in stable condition Thursday evening.

The Washington Post said the company is looking into what happened.

Commuter Justin Gavin said the suspect handed him a newspaper less than an hour before the attack.

"He seemed fine to me," he said.