A man who was reportedly beaten up while celebrating the Giants’ World Series victory in the Upper Haight neighborhood Oct. 28 has died, police said Wednesday, and homicide investigators have been assigned to the case.

The 37-year-old man, whom police have not identified, told friends he had been on Haight Street after the Giants clinched the title in Detroit and was surrounded by five men who beat him with a metal object. He reportedly died several days later from the major head trauma he suffered.

A motive for that attack remains unclear.

Police are hoping witnesses will come forward. The incident occurred sometime between 9:30 p.m. and 10:30 p.m. near Masonic Avenue.