Notorious killer Charles Manson -- the ringleader behind a 1969 Los Angeles killing spree – was supposed to undergo surgery Thursday, but it was determined that he was too weak for the procedure, TMZ.com reported.

The website reported that the 82-year-old was taken from Corcoran State Prison to a hospital days ago and he was supposed to have surgery for intestinal bleeding.

The report said Manson remains in the hospital in Bakerfield.

Manson was convicted of orchestrating the 1969 murders of pregnant actress Sharon Tate and six others.

Tate's sister Debra Tate told The Associated Press on Tuesday night that, as a Catholic, she makes "no ill wishes" for the people who killed her sister, and will reserve her feelings until hearing Manson has died.

"I would probably say a prayer for them and shed a tear and ask God to have mercy on their souls, but so far I haven't allowed myself to feel anything because it's unsubstantiated," Tate said. "I'm not allowing myself to feel anything until I know that it's true."

Manson was convicted of leading a cult in which disaffected young people living in a commune followed his orders and were ultimately turned into killers.

Manson and three female followers, Susan Atkins, Patricia Krenwinkel and Leslie Van Houten, were convicted of murder and sentenced to death for killings at two gruesome scenes in the summer of 1969. Another defendant, Charles "Tex" Watson, was convicted later.

All were spared execution when a U.S. Supreme Court ruling temporarily banned the death penalty in 1972.

The Associated Press contributed to this report