Steve Dunleavy, a hell-raising Australian who transfused his adrenaline into tabloid newspapers and television as a party crasher to American journalism, died on Monday at his home in Island Park, N.Y. He was 81.

His son Sean said the cause had not been determined.

Mr. Dunleavy relished his role as a mouthpiece for the media mogul Rupert Murdoch, working for him as a writer and editor at the celebrity-filled Star magazine; as an editor and right-wing columnist at The New York Post; and as the lead reporter for the tabloid-like TV newsmagazine “A Current Affair” (now off the air) on Fox.

Mr. Dunleavy exposed Elvis Presley’s addiction to prescription drugs in Star and in a best-selling book that rankled Presley fans; scored exclusive interviews with the mother of Sirhan Sirhan, Robert F. Kennedy’s assassin, and Albert DeSalvo, the confessed Boston Strangler; and championed police officers, smokers and gun owners, among others.

During his run on “A Current Affair,” from 1986 to 1995, he wrestled a bear in one segment and, in another, was bitten by a witness in a rape case when he confronted her with nude photographs of her.