A 22-year-old man was fatally shot at his home Wednesday afternoon on the city's southside.

The man's mother and stepfather arrived home shortly before 4 p.m., and found their son lying in the doorway of their house in the 400 block of West Kentucky Street, said Sgt. Chris Widmer, a Tucson Police Department spokesman.

The neighborhood is north of West Irvington Road and east of South 12th Avenue.

Neighbor Mark Templeton said he heard a woman screaming, and he went to the house to see if he could help.

"She was trying to give her son CPR, but he was already dead," said Templeton, 49.

The victim's mother was on the phone with 911, Templeton said.

Soon after police arrived at the house and found the victim inside the home with a gunshot wound. He was pronounced dead, Widmer said.

Homicide detectives were at the scene working the case, and were expected to remain there for hours, Widmer said.

No further information was released.