( 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 .
NEW : Police say first - degree murder charges are filed against year - old Michael James . Police identify the deceased detective as James Stevenson . The officer was out celebrating his 38th birthday . He was hit with a piece of wood , they say .