Denver police have identified a suspect in the weekend killing of an off-duty officer.

Chief Gerry Whitman says 19-year-old Raul Garcia Gomez is the man who shot Detective Donald Young several times from behind on Sunday. Young died a short time later at a hospital.

Whitman called the attack an "ambush," and Denver Mayor John Hickenlooper referred to it as "cold-blooded murder."

Police spokesman Sonny Jackson says Gomez's whereabouts are unknown -- but that he should be considered armed and extremely dangerous.

Gomez is described as a Hispanic male, five-foot-six, 150 pounds, with shaved dark brown hair, brown eyes, a thin mustache, and tattoos on his left hand or forearm.

Police say he could be driving a white, four-door 1995 Dodge Neon.

The car may have temporary Colorado license tags with the number 474-735C.

Crime Stoppers is offering a 50-thousand dollar reward for information, and tipsters can remain anonymous.

Anyone with knowledge of the case is being urged to call Crime Stoppers at 720-913-STOP in Denver, 719-634-STOP in Colorado Springs or 719-542-STOP in Pueblo.