Haidl's family issued a brief statement saying he unexpectedly died Tuesday night, the Orange County Register reported ( http://bit.ly/ZjtMSU). His cause of death was not released.
"He died as he lived, surrounded by people he loved," the family's statement read.
Haidl was a millionaire from his work in the car auction industry and had brought in big-money backers for Carona's bid for sheriff. Carona later picked him to head the Sheriff's Department reserve program, where he worked on an unpaid volunteer basis as an assistant sheriff.
Haidl resigned in 2005 as his son, Greg, faced charges in the rape of an unconscious 16-year-old girl in his father's Corona del Mar home. Greg Haidl and two friends were found guilty of sexual assault.
Two years later, the former assistant sheriff pleaded guilty in a tax fraud case, and made a deal to cooperate in a federal probe of Carona. Haidl admitted he was trying to recoup some of the money he spent on his son's criminal defense when he filed false tax returns.
Haidl wore a hidden microphone in three conversations with Carona that led to the then-sheriff's conviction for witness tampering.
He also publicly apologized for any wrongdoing before withdrawing from the public eye.
Information from: The Orange County Register, http://www.ocregister.com