A punch to the face that took the life of a homeless man last month in Reseda is being investigated as a homicide, authorities said.

Witnesses saw a man punch Harold Gene Loftis, 69, at a bus stop at Roscoe and Reseda boulevards about 10 p.m. April 14, said Los Angeles Police Det. Mike Fesperman. The attack appeared to be unprovoked, Fesperman said -- witnesses did not hear the attacker demand money and said he did not appear to know Loftis.

The punch knocked Loftis off-balance and he fell, hit his head on the sidewalk and lost consciousness, Fesperman said. Loftis was taken to a hospital where he underwent two brain surgeries before he died May 1, Fesperman said.

On Monday, the Los Angeles County coroner's office ruled Loftis' death a homicide.

Witnesses said the suspect was a Latino man in his 20s with a muscular build. At the time of the attack he wore a white T-shirt and blue jeans.

Fesperman said no similar assaults on the homeless have been reported in the area where Loftis was attacked.

Anyone with information on the assault is asked to call investigators at (818) 832-0537.

molly.hennessy-fiske@latimes.com