Portland police are trying to determine what caused the injuries to a homeless man who was hospitalized over the weekend.

Police say Jess Mackinnon, 46, was found in the alley near Hub Furniture bleeding and unconscious at 1:15 p.m. Sunday. He was taken to Maine Medical Center and while his condition has improved, police have not been able to interview him.

Investigators cannot say for certain whether Mackinnon was assaulted or he fell, injuring himself on rocks and other debris in the alley. Police said Mackinnon was known to spend time in the alley.

Anyone with information is asked to call 874-8539.