Jeremy Williams, a middleweight submissions expert in the International Fight League, died Saturday of unknown causes at 27.
There were few immediate details surrounding the manner and cause of Williams' death and where his body was discovered.
Williams, of Laguna Nigel, Calif., fought in the King of the Cage mixed martial arts circuit before joining the IFL and had a 7-2 MMA record.
He competed for the Southern California Condors in the IFL and won his last fight by first-round submission on March 17 when he choked out Kazuhiro Hamanaka in 59 seconds.
The most significant wins of his career came over Yves Edwards and Shannon Ritch.
In a statement, IFL commissioner Kurt Otto said: "This is a very sad day for the Williams family, Jeremy's teammates and all of the mixed martial arts community. Jeremy was a tremendous competitor and teammate, as well as being a very strong person who lifted the spirits of everyone around him.
"Our thoughts and prayers are with Jeremy's wife, Lauren, their young daughter and the rest of his family, as well as his coaches Marco Ruas and Debi Purcell and all his teammates. Everyone at the IFL, as well as the entire MMA community, will do everything we can to support them in their hour of need."
Williams is survived by his wife, Lauren, and one daughter.