CHICAGO (CBS) — A 60-year-old man is dead after being shot in the head in the South Side’s Cottage Grove Heights neighborhood early Saturday.

Around 12:05 a.m., the man was walking in the alley behind the 9500 block of South University Avenue when he was shot in the head, police said.

Police said they had not identified any witnesses to the actual shooting, but someone saw an unknown number of people running down the alley after the shots were fired.

The victim was taken to the University of Chicago Medical Center in critical condition, and was later pronounced dead at the hospital, police said.

He was identified as Donald Ruben of the Park Manor neighborhood.

No one was in custody Saturday afternoon, and Area South detectives were investigating.