Mitchell lived in Petaluma with his wife, Lisa. He suffered a heart attack, said Merle Lane, a relative by marriage.
"He was sitting in his chair and doing something, I think watching TV, and he just, 'Ehhhh.' That was it. His heart quit him just like that," Lane said.
The brothers' adult business began in Antioch, Calif., where Jim graduated from the high school in 1962. They sold nude photos to magazines in San Francisco during the late '60s, opened the O'Farrell Theater in San Francisco in 1969, and started making porn loops. They reached cult status in 1972 with "Behind the Green Door," starring Ivory Snow model Marilyn Chambers, followed by "Resurrection of Eve" in 1973, and several other full-length films notable for high production values, wit and social commentary during the '70s Golden Age.
The Mitchell brothers produced hundreds of sex films, and faced and beat more than 100 arrests on obscenity charges, which they never avoided. The local police would call them and they would come in to get booked. Their defense of their copyrights led to court judgments against people who bootlegged their films.
In 1991, Jim Mitchell shot and killed his brother Artie at Artie's home in the bay area. Prosecutors called the shooting an attempt by Jim to control his younger brother. Jim Mitchell's lawyers claimed Artie, 45 at the time, was in an alcoholic tailspin and threatened to kill Jim. Mitchell's lawyers also called the shooting a desperate attempt to convince Artie, who had fallen into a tailspin of alcohol and drugs, to seek treatment.
When Jim Mitchell entered Artie's house, he was armed with a rifle, a handgun, a knife and a box of ammunition. He fired eight shots, three of them hitting his brother, one fatal shot in the head. When police arrested him as he walked from the home, he had a .22-caliber rifle in his pants leg and a revolver in a shoulder holster.
Jim Mitchell was convicted of involuntary manslaughter and served three years in San Quentin. He was released in 1997.
Since his release, Mitchell has lived a quiet life on his ranch, said family members and friends.
Mitchell was no longer involved in the day-to-day operations of the Mitchell Brothers business, which includes a porn film operation and the O'Farrell Theater in San Francisco. A manager at the club declined to comment on Mitchell or his death, saying, "It just happened. We're just trying to take care of business." He declined to give his name.
