Former world heavyweight champion Michael Dokes, 54, has died after losing a battle with liver cancer, the World Boxing Association said on its website (www.wbanews.com).
The American won the WBA version of the title in 1982 when he defeated Mike Weaver and then lost it to South Africa's Gerrie Coetzee a year later.
He went on to fight Evander Holyfield and Riddick Bowe but never held a world title again.
Dokes retired in 1997 with a professional record of 53 wins, six defeats and two draws.
He spent eight years in prison from 2000-08 after pleading guilty to attempted murder, second-degree kidnapping and intent to commit sexual assault against his girlfriend.
Photograph: Holly Stein /Allsport