One of Gary Busey's ex-wives, Tiani Warden, died behind bars in Texas ... and according to her autopsy, it was a cocaine overdose that killed her.
Tiani was found unresponsive in her jail cell at the Hunty County Detention Center back on Nov. 4, the day after police arrested her for public intoxication ... the Hunt County Sheriff's Office tells TMZ.
The actress died from the toxic effects of cocaine ... this according to the Dallas County Medical Examiner. They've ruled her death accidental, and say chronic ethanolism -- heavy drinking -- likely contributed to her death.
It's interesting ... when Tiani was arrested, cops said they were responding to a call of a person lying in a ditch, and the person turned out to be Warden. Police say Tiani was intoxicated and they called for an ambulance, but she refused treatment and was arrested and brought to the Hunt County Detention Center.
Authorities say Tiani was in a holding cell by herself when she died, and her body was discovered after she had already seen a judge and eaten lunch. Cops say they checked her cell at 2:36 PM and found her unresponsive, and the autopsy says she died at 3:29 PM.
Gary married Tiani back in September 1996 and they divorced in 2001.
Tiani enjoyed an acting career, and was known for her work in "The Chain," "The Rage" and "Rough Riders."