The Los Angeles Times reports that several weeks of interviews and other investigative work have not uncovered any evidence the death was a homicide.
Sheriff's chief of detectives William McSweeney says cold cases like Wood's are never really closed and detectives are looking at some aspects of the case.
Natalie Wood died on the evening of Nov. 28, 1981, when the 43-year-old actress was boating off Catalina Island with her husband Robert Wagner and actor Christopher Walken.
The investigation was reopened in November, when detectives say several sources came forward with new information.
Information from: Los Angeles Times, http://www.latimes.com