A man attending an illegal cockfight in central California died after being stabbed in the leg by a bird that had a knife attached to its own limb.
Jose Luis Ochoa, 35, was declared dead at a hospital about two hours after he was injured on 30 January, the Kern County coroner said. An autopsy concluded that Mr Ochoa died of an accidental "sharp force injury" to his right calf.
"I have never seen this type of incident," Sergeant Martin King, a 24-year veteran of the sheriff's department, told The Bakersfield Californian newspaper.
Mr Ochoa and the other spectators fled when authorities arrived at the scene of the fight. Deputies found five dead roosters and other evidence of cockfighting at the location. No arrests were made.
It was unclear if a delay in seeking medical attention contributed to Mr Ochoa's death.
Cockfighting is a sport, illegal in the United States, in which specially bred roosters are put into a ring and encouraged to fight until one is incapacitated or killed.
According to Kern County Superior Court records, Mr Ochoa paid $370 (£230) in fines last year after pleading no contest to one count of owning or training an animal for fighting. Attending or organising a cockfight, or training an animal to participate in one, are all misdemeanours under Californian law.