(CNN) The drowning of actress Natalie Wood has long been one of Hollywood's great mysteries but authorities say they are now investigating her death as "suspicious" after new witnesses came forward.

Wood, a top-tier actress who starred in "West Side Story" and "Splendor in the Grass," died in 1981 after falling into the ocean off Catalina Island in California while boating with husband Robert Wagner and friend Christopher Walken. She was 43.

Police had initially ruled Wood's death as accidental but years later, bruises on Wood's body led the Los Angeles County coroner's office to change the cause of death from "accidental drowning" to "drowning and other undetermined factors."

In 2011, the Los Angeles Sheriff's Department reopened its investigation into Wood's death , saying they had been contacted by people claiming to have "additional information" about the drowning.

On Thursday, authorities said that after reviewing more than 100 tips, they obtained new witnesses statements that "portray a new sequence of events on the boat that night."

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