Ted Kacynski, a terrorist known as the ‘Unabomber’ was found dead in his cell according to the Federal Bureau of Prisons.

CNN reported that 81 year-old Kaczynski was “found unresponsive” in his cell at the Federal Medical Center in Butner North Carolina on Saturday morning.

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How did the ‘Unabomber’ die?

NPR reported that a spokesperson for the federal Bureau of Prisons told the Associated Press that Kaczynski was pronounced dead at 8 a.m. with the cause of death being not immediately known.

“Responding staff immediately initiated life-saving measures,” the bureau reported in a statement. “Staff requested emergency medical services and life-saving efforts continued. Mr. Kacynski was transported by EMS to a local hospital and subsequently pronounced deceased by hospital personnel.”

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How was the ‘Unabomber’ caught?

From 1978 to 1995, Kacynski attacked random civilians, businessmen and academics with homemade bombs injuring 23 people and killing 3, “with the stated goal of fomenting the collapse of the modern social order,” according to The New York Times.

ABC News reported that during an interview with “20/20 on ID Presents: Homicide” in 2016, Linda Patrik, Kaczynski’s sister-in-law spoke out on when she “suspected Kaczynski was responsible for the serial bombings.”

Patrik reportedly “recognized familiar-sounding ideas in the manuscript from letters her husband David Kacynski had received from his brother,” and after the family contacted the FBI, “a 9-man SWAT team apprehended Kaczynski in his cabin in Montana.”

“I’d thought about the families that were bombed. There was one in which the package arrived to the man’s home and his little 2-year-old daughter was there. She was almost in the room when he opened the package. Luckily she left, and his wife left. And then he died,” Patrik said. “And there were others. And so I spent those days thinking about those people,” Patrik said.