Watch "CNN Spotlight: Charles Manson" at 7:30 p.m. ET on Saturday and Sunday.
(CNN) -- Inside the Charles Manson room at the Museum of Death in Hollywood, Anne Forde looks at crime scene photos from the 1969 Tate-LaBianca murders.
"I was a kid when he was involved in these crimes," says Forde, who grew up in County Cork, Ireland. "It's just been a fascination for me ever since."
"His eyes just stand out and look crazy," says Debbie Roberts, who was visiting the museum from Kentucky. "I can see how people followed him."
A few miles away on Saturday mornings, Scott Michaels is hosting the "Helter Skelter Tragical History Tour." For $65, you can buy a bus seat to see where the murders took place, as Michaels tells the story of Helter Skelter.
"We have people from around the world that sign up," says Michaels. "We added an additional anniversary tour, which is sold out."
August 9 marks the 45th anniversary of the murders of Sharon Tate and four others on Cielo Drive in the Benedict Canyon neighborhood of Los Angeles. Tate, who was 8½ months pregnant and married to movie director Roman Polanski, was stabbed 16 times as she pleaded for the life of her unborn child. The next night, supermarket executive Leno LaBianca and Rosemary LaBianca were tortured and killed inside their home near Hollywood.
Since then, Charles Manson, who was convicted of orchestrating the murders, has been the focus of continued fascination.
"People seem to be fascinated by things that are strange and bizarre," says Vincent Bugliosi, sitting in his Los Angeles-area living room.
Bugliosi is the man who prosecuted Manson and his "family" and co-wrote the book "Helter Skelter: The True Story of the Manson Murders." With more than 7 million copies sold, it is still the best-selling true crime book.
Bugliosi believes people are still fascinated by the Tate-LaBianca murders for two reasons: the gruesome nature of the murders and the lasting image people have of Charles Manson, with the maniacal stare and the swastika on his forehead.
"The name Manson has become a metaphor for evil, and there's a side of human nature that's fascinated by pure unalloyed evil," says Bugliosi.
There are, however, people who continue to support Manson. He has received more mail than any other inmate in state history. According to California's Department of Corrections and Rehabilitation, Manson still gets about 35 letters a week.
Online, there are multiple Charles Manson websites, including mansondirect.com, which features audio messages from Manson in prison. Manson's Facebook page has 70,000 "likes."
"This is an unusual case. It's not a whodunnit. This is a why dunnit," says Brian Davis, the host of the Internet radio channel TLB, which stands for Tate La Bianca. Davis operates the channel, which has an irregular schedule and averages a few hundred listeners, from his home in Roanoke, Virginia.
Davis says he has been studying the Manson case off and on for 10 years and labels himself as "down the middle." He thinks a lot of the Manson image was created by Bugliosi and the media, and he wonders if Manson really brainwashed the killers.
"I don't think Manson ordered those murders," he says.
Manson, who turns 80 in November, has been denied parole 12 times. His next parole hearing isn't scheduled until 2027, when, if he's still alive, he'll be 92 years old.