April 3, 2016 is 20th anniversary of the day the Unabomber was arrested.
Terrorist Ted Kaczynski is serving a life sentence for a bombing spree that injured two dozen people and killed three men. Two of those bombing victims were killed in Sacramento.
Former FBI agent Max Noel says what Kaczynski did was "pure evil." Noel arrested Kaczynski at his remote cabin in Montana on April 3,1996.
Noel has a picture of the Unabomber being led away in handcuffs. His clothes were torn and tattered.
"That's the way he dressed," Noel said. "His clothing was rotting off of him. He smelled. He was very unhygienic."
The Unabomber was responsible for a series of 16 bombings that began in 1978.
"He manufactured his own explosives. There was no connection between any of his victims," said Noel.
For nearly two decades after that first bomb, Kaczynski avoided justice.
"Trying to connect him through the victims was impossible. Trying to connect him through forensic evidence was impossible," Noel said.
In 1985, Hugh Scrutton -- a computer store owner was killed when a bomb went off in the parking lot by his work.
The Unabomber's final bomb killed Gil Murray in 1995. Murray was the president of the California Forestry Association.
Noel and his two FBI counterparts published a book two years ago.
In the book, they talked about how the FBI had to break one of its own rules.
"We broke lots of rules at the FBI. It would take me hours to explain," Noel said.
The FBI decided to allow the Unabomber's manifesto to be published in the New York Times and the Washington Post.
The Unabomber's brother ended up recognizing the writing style and notified the FBI.
The FBI found Kaczinsky hiding out in this Montana cabin.
"To walk up to a cabin in the middle of the wilderness and attempt to extract the most successful booby trap artist was not something I relish doing. But we had to do it," said Noel.
They got Kaczinsky to leave and captured him before he could kill himself.
The Unabomber was eventually brought to Sacramento for trial. It's where he also pleaded guilty. The Unabomber pleaded guilty and struck a deal with the government.
So, instead of being executed for his crimes, he is serving life in a federal prison in Colorado.