Questions about bruises on the body of actress Natalie Wood, whose body was found floating off Catalina Island in 1981, led the Los Angeles County coroner's office to change the cause of death from "accidental drowning" to "drowning and other undetermined factors."

"With the presence of fresh bruises in the upper extremities in the right forearm/left wrist area and a small scratch in the anterior neck, this examiner is unable to exclude non-accidental mechanism causing these injuries," wrote Dr. Lakshmanan Sathyavagiswaran, the chief medical examiner.

"The location of the bruises, the multiplicity of the bruises, lack of head trauma, or facial bruising support bruising having occurred prior to entry in the water. Since there are unanswered questions and limited additional evidence available for evaluation, it is opined by this medical examiner that the manner of death should be left as undetermined."

Based on a number of factors, including the lack of a life jacket, lack of a suicide note, "this Medical Examiner is unable to exclude non-volitional, unplanned entry into the water," the report says.

"How injury occurred will be listed as found floating in the ocean," it adds. "Circumstances not clearly established."

The change in the cause of death was made public last year, but the report outlining the reasons -- which was dated June 15, 2012 -- was not made public until Monday.

The case is "open and ongoing; nothing definitive has closed it," said Los Angeles County Sheriff's Department spokesman Steve Whitmore.

He said that Wood's widower, actor Robert Wagner, is not a suspect.

A security hold was placed on the report when it came out because of concern "that the frenzy that's surrounding this could contaminate the investigation," Whitmore said.

The hold was lifted last week and the report made public Monday after next of kin were notified.

Homicide investigators decided to take a new look at one of Hollywood's most enduring mysteries in November 2011 after they were contacted by people who said they had additional information about the actress's death, the sheriff's department said last summer.

The announcement persuaded tipsters to come forward with additional "intriguing" information, sheriff's spokesman Whitmore told CNN last January.

Investigators did not comment directly on statements made in news reports in November by Dennis Davern, the captain of a yacht owned by Wood and her husband.

Davern offered a previously unreported account of how Wood's death was reported, saying that Wagner waited hours to call the Coast Guard after Wood went missing off Catalina Island following an argument between the couple.

Wood died on November 29, 1981, off the isthmus of Catalina Island. Dressed in a flannel nightgown, socks and a down jacket, her body was found floating about a mile from the yacht, according to police reports.

The autopsy report showed the 43-year-old actress had two dozen bruises on her body, including a facial abrasion on her left cheek and bruises on her arms.

"My sister was not a swimmer and did not know how to swim, and she would never go to another boat or to shore dressed in a nightgown and socks," said Lana Wood, referring to theories that the actress may have voluntarily jumped from the boat, last year.

Although the county coroner's office ruled at the time that Wood's death was an accident, others said then that that made no sense.

In 2010, Lana Wood told CNN she believed an argument between her sister and Wagner on the yacht's back deck preceded Wood's drowning. She told CNN in 2011 that she did not suspect foul play.

"I just want the truth to come out, the real story," she said.