(CNN) -- First-degree murder charges have been filed against a man who Baltimore, Maryland, police believe killed an off-duty detective by striking him in the head during a dispute over a parking space, authorities said Sunday.

Sian James, 25, is suspected in the death of Brian Stevenson, an 18-year police veteran, who was out celebrating his 38th birthday with a friend late Saturday night when an argument ensued over a parking spot outside a restaurant, police said.

According to witnesses, James picked up a piece of concrete and threw it at Stevenson, hitting him in the head.

The attack occurred around 10 p.m. Stevenson was rushed to Johns Hopkins hospital, where he died.

Police say James fled the scene and was apprehended later at a nearby night club.

"Dozens of officers, investigators and civilian personnel put their lives on hold and worked throughout the night to identify Mr. James as a suspect and bring him to Justice. I'm very proud and honored to lead such a dedicated group of public safety professionals," said Baltimore Police Commissioner Frederick Bealefeld.

He described Stevenson as a "fantastic" detective.

"To lose his life in this manner is senseless," Bealefeld said at a press conference early Sunday morning.

"Detective Stevenson was a good man, a good investigator and a great public servant to the people of Baltimore," he said. "His death is an incredible tragedy to not only his family, but to the entire city and to every man and woman who wears the police uniform."

It was not immediately clear whether the attacker knew Stevenson was a police detective.