The Los Angeles County coroner filed documents in June making the change. Officials now say the case remains an "open and ongoing investigation," reports TMZ.
Members of Wood's family tell TMZ that the cause of death was revised because some of the bruises on Wood's body were inconsistent with an accidental death by drowning. They said Wood definitely died by drowning, but how she got into the water remains a mystery.
Wood died on November 29, 1981 following a party on a boat off California's Santa Catalina Island. Actors Robert Wagner - her husband - and Christopher Walken - her "Brainstorm" co-star - were also on board the boat. TMZ says Wagner is not considered a suspect in the case.
It's been believed that the 43-year-old Wood drowned while trying to secure a dinghy on the boat.