Five-time world champion Johnny Tapia has been found dead at his Albuquerque home at the age of 45.
Police spokesperson Robert Gibbs said there did not appear to be any suspicious circumstances.
Tapia won world titles in three weight classes but his turbulent career was marked by cocaine addiction, alcohol, depression and run-ins with the law, including several stints in jail.
The American was banned from boxing for three-and-a-half years in the early 1990s because of his cocaine addiction, but returned to the ring to win the WBO bantamweight title in 1994, and won four more championships over the next eight years.
Tapia - who had the Spanish phrase 'mi vida loca' (my crazy life) tattooed on his stomach - turned professional in 1988 and after going unbeaten in his first 48 fights - claiming the WBO and IBF super flyweight titles plus the WBA bantamweight crown in the process - he was eventually defeated by Paulie Ayala in June 1999.
He won the IBF featherweight title in April 2002 with a majority decision victory over Manuel Medina but dropped a decision to Marco Antonio Barrera six months later and from there his career went slowly downhill.
His last fight came in June 2011 when he scored an eight-round decision over Mauricio Pastrana in his home town of Albuquerque, leaving him with a career record of 59 wins, five losses and two draws.
His life was also marked by tragedy. He was orphaned at eight when his mother was kidnapped, raped and left for dead after being stabbed 26 times with a screwdriver.
In 2007, he was declared clinically dead for a third time after an apparent cocaine overdose and the following day he lost his brother-in-law and nephew when they were killed in car accident on their way to hospital.