A man found burning on an Altadena sidewalk had his feet bound and a ligature on one of his wrists, authorities said Thursday.

Although the autopsy on the man, who was found Sunday, has been completed, investigators with the L.A. County Sheriff's Department still do not know what caused his death.

He was discovered by a passerby at 6 a.m. in the 2600 block of Windsor Avenue, not far from Devil’s Gate Dam, the Jet Propulsion Laboratory and a popular trailhead into the San Gabriel Mountains.

Assistant Chief Coroner Ed Winter indicated that further tests -- toxicology, histopathology and neuropathology -- are needed to determine how the man died. Results from the tests will be available in six to eight weeks.