Officers responded to a report of a stabbing near 11th and Mission streets at 11:45 p.m. on Jan. 18, but instead found a man suffering from head trauma, police spokesman Officer Albie Esparza said.
Once the victim was taken to San Francisco General Hospital, doctors determined that he had been assaulted, Esparza said.
A significant other said that the victim, identified by the medical examiner's office as 34-year-old San Francisco resident Scott Nau, was also missing personal items, including his cellphone, according to Esparza.
Nau succumbed to his injuries shortly after 7 p.m. Sunday, and the medical examiner has ruled the case a homicide, Esparza said.
No arrests have been made in the case, and no suspect information was immediately available this morning, he said.
Anyone with information about the case is encouraged to call the Police Department's homicide detail at (415) 553-1145, the anonymous tip line at (415) 575-4444 or to send a tip by text message to TIP411.