SAN FRANCISCO (CBS SF) — A San Francisco man was arrested in the unprovoked, fatal assault of a 34-year-old man in city’s Mission District, police said Tuesday.

The incident happened on September 28 in the area of Treat Ave. and Kamille Ct., just north of Cesar Chavez Blvd. San Francisco police said the medical examiner’s office contacted homicide investigators on October 1 to advise that a man who died at that location was likely the victim of an unreported assault.

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Investigators found witnesses who said the victim was with a group of people that evening and was approached by a person who punched him in the face, causing him to fall backward and hit his head on the ground, police said. He later died of his injuries in the hospital.

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Homicide investigators identified the suspect as 32-year-old Asafo Ia of San Francisco. On Monday at about 10:30 p.m., Ia surrendered himself to investigators, according to police.

Ia was he booked at San Francisco County Jail on charges of murder and failing to register as a sex offender.

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Police asked anyone with information about the case to call the SFPD Tip Line at 1-415-575-4444 or send a text anonymously to  TIP411 and begin the text message with SFPD.