Wood drowned at the age of 43 during a yacht trip with her husband, Robert Wagner, and actor Christopher Walken. The case remains one of Hollywood's biggest mysteries.
The report from the medical examiner says there is no question that Wood drowned. But it states that another review of the medical evidence reveals some gaps and adds to the mystery of what happened on a very dark night off the coast of Catalina.
The coroner has been reviewing evidence collected 30 years ago. In a supplemental report, the coroner says there was specific attention to fresh bruises on her right forearm, left wrist area and a small scratch on the back of her neck.
Investigators initially had theorized that Wood fell in the water and tried to claw her way up onto a dinghy. But examiners never got fingernail evidence. And investigators have not been able to access the dinghy to see if there are signs of scratches.
The amended report opens a question as to whether a person could have been involved. The coroner stated he could not exclude a non-accidental mechanism causing the injuries.
The Los Angeles County Sheriff's Department says they have been interviewing witnesses and others to get definite answers. But spokesman Steve Whitmore says details of the investigation remain confidential.
"We've talked to some people, and we've followed some leads, but I can't get into the specifics of it because it's important that we remain the integrity of the investigation," Whitmore said.
The sheriff's department reopened the case just over a year ago, saying there were several sources with information that was credible enough to take a second look. Among them was the captain of boat, who was selling a new tell-all book. He said that there was a drunken, violent argument between Wood, Wagner and Walken before Wood disappeared.
"I really suspect it was some type of foul play if you really analyze the circumstances," said Dennis Davearn said in an interview in November 2011.
Authorities have stressed Wagner is not a suspect. Wagner has stated that he supports the investigation. The supplemental coroner's report says there are conflicting statements as to when Wood went missing from their boat and whether there had been verbal arguments.
The coroner says bruising likely happened before she went in the water. But as to the cause and how she ended up in the water, the evidence is limited, the coroner says. Consequently, the cause of death will be changed to drowning and other undetermined factors.
Wagner did not respond to requests for comment, and there was no word from his publicist about the report.
The sheriff's department says it remains an open case and will not state what their next step is.