Atlanta Police Sgt. Lisa Keyes said in an e-mail Sunday that Forrest may have been robbed and was shot "multiple times in the back" Saturday night in Atlanta.
Keyes says there are no suspects.
Mark Guilbeau, an investigator with the Fulton County Medical Examiner's office, said an autopsy is planned for Sunday.
Forrest, a native of Augusta, Ga., who lived in Atlanta, was a member of the 1992 Olympic team. He was also a former WBC super welterweight champion.
The 38-year-old took two wins over Sugar Shane Mosley in 2002. On Sept. 13, 2008, Forrest reclaimed his WBC 154-pound title by beating Sergio Mora.