UFC Hall of Famer Stephan Bonnar Dead at 45

Stephan Bonnar, whose fight with Forrest Griffin at “The Ultimate Fighter 1” finale propelled the UFC to a new level of popularity, has died at 45 years old.

The UFC announced Bonnar’s passing in a statement on Saturday. The cause of death was revealed to be “presumed heart complications while at work.”

"Stephan Bonnar was one of the most important fighters to ever compete in the Octagon," said UFC President Dana White. "His fight with Forrest Griffin changed the sport forever, and he will never be forgotten. The fans loved him, related to him and he always gave them his best. He will be missed."

Bonnar is perhaps best known was his time on “TUF 1,” where he reached the finals of the reality show and received a UFC contract after losing a unanimous decision to Griffin in a memorable clash on April 9, 2005. That bout was later enshrined in the UFC Hall of Fame’s “Fight Wing.”

That led to a seven-year career with the Las Vegas-based promotion that saw “The American Psycho” compile an 8-7 mark in the Octagon. He earned wins over the likes of Keith Jardine, James Irvin and Krzysztof Soszynski and also squared off against noteworthy foes such as Anderson Silva, Jon Jones, Mark Coleman and Rashad Evans.

Bonnar initially announced his retirement following a loss to Anderson Silva at UFC 153 in October 2012, but he made a brief return to MMA two years later, falling to Tito Ortiz via split decision at Bellator 131 on Nov. 15, 2014.