"I've heard as he's gotten older, he's slowed down a bit," Thornton said.
But that doesn't mean he's necessarily behaving. Manson has had two rules violations in the last two years, one for possessing a weapon, the other for threatening a peace officer. He has also never taken advantage of any educational or rehabilitation programs offered to prisoners.
"He is not what we would describe as a model inmate," she said.
Thornton said Manson hasn't had any visitors in the past three months, and although people do still make requests, the numbers have dwindled. Lists of visitor requests and actual visitors are kept confidential.
Every once in awhile, she said, Manson will throw out his list of approved visitors and start all over again.
Bugliosi, who is a married father of two with several best-selling books to his credit, said he received four letters from Manson in the 1970s and 1980s.
"I did not respond, and I turned them over to the Department of Corrections," he said, declining to comment on the letters' contents.
A photo of Manson released this spring shows that while he's noticeably aged into an elderly man he still sports his beard -- albeit gray and shorter -- and the infamous swastika he carved into his head during the trial.
But to the California State prison system, Manson is just another inmate -- one of 12,237 people incarcerated for first-degree murder.
Manson was born Nov. 12, 1934, to a 16-year-old mother who would later try to pawn him off on others, rejecting him when he ran away from a boys' school to be with her. Born Charles Milles Maddox, the Manson surname came from his stepfather.
"He has said publicly that he didn't have any parents. He didn't know who his father was," Bugliosi said. "His mother, she ran around a lot and lived with a succession of what would have been uncles to him."
Bulgiosi said that Manson committed his first known crime -- burglarizing a grocery store --at age 12, followed by armed robbery at age 13.
While it is simply speculation as to what makes Manson tick, Bulgiosi said he believed Manson's crimes were motivated both by a sense that he was "not dealt a full hand in life" and by an "enormous hostility toward society."
"Some people are just bad human beings," he said. "And he's a bad person."
Manson married a young girl in 1955 and promptly became a father to Charles Milles Manson Jr. But his stint as family man didn't last long, and he was back in prison the next year.
He got out of prison to find his wife and child had taken off, so Manson hooked up with another woman who would give birth to his second son, Charles Luther Manson. Manson was back in jail again by 1958, where he would stay until 1967, reportedly raping a fellow inmate during his incarceration.
According to a Manson report on the Biography Channel's Web site, probation reports described him as "constantly striving for status" and suffering from a "marked degree of rejection." The reports also described him as "dangerous" and "safe only under supervision."
It was after his release when Manson began building the Family, what would become a quasi-cult obsessed with chaos and the "Helter Skelter" plan to create a race war between blacks and whites that was supposed to lead to Manson's domination.