San Antonio police are investigating a late Tuesday afternoon shooting in which a man was shot in the back of the head.

Police said the 27-year-old man -- who was found alive in the 1700 block of Castroville Road, on the city's West side -- is not cooperating with investigators.

He did tell police that he was involved in a struggle with another man and was then shot.

He said his alleged shooter fled the scene immediately following the shooting.

Police investigators spent Tuesday evening combing the area for both the scene of the shooting and the man's alleged assailant.

KSAT reporter Tim Gerber contributed to this story.