The Unabomber's cause of death has been revealed, hours after he was found dead in his prison cell.
Theodore 'Ted' Kaczynski was discovered unresponsive at around 8am (local time) at a federal prison in North Carolina on Saturday.
America's most prolific bomber was 81 years old.
He had been moved to the federal prison medical facility in North Carolina after spending two decades in a federal Supermax prison in Colorado for a series of bombings that terrified the United States.
He had pleaded guilty to all charges in 1998 and was sentenced to eight consecutive life terms in prison without the possibility of parole.
While his cause of death was not immediately declared, sources close to the matter have confirmed Kaczynski died by suicide, the New York Times reports.
Kaczynski, who was 81 and suffering from late-stage cancer, was found unresponsive in his cell at the Federal Medical Center in Butner, North Carolina around 12.30 am on Saturday.
Emergency responders performed CPR and revived him before he was transported to a hospital, where he was pronounced dead later Saturday morning, sources told the AP.
Kaczynski was arrested in 1996 at the primitive cabin where he was living in western Montana.
The Harvard-educated mathematician retreated to a dingy shack in the wilderness and ran a 17-year bombing campaign that terrorised the US and changed the country forever.
He pleaded guilty to setting 16 explosions that killed three people and injured 23 others in various parts of America between 1978 and 1995.
Years before the 9/11 attacks and the anthrax mailing, the Unabomber’s deadly homemade bombs changed the way Americans mailed packages and boarded aeroplanes, even virtually shutting down air travel on the West Coast in July 1995.
He evaded capture for almost two decades.
He forced The Washington Post, in conjunction with The New York Times, to make the agonising decision in September 1995 to publish his 35,000-word manifesto, “Industrial Society and Its Future,” which claimed modern society and technology was leading to a sense of powerlessness and alienation.
But it led to his undoing. Kaczynski’s brother David and David’s wife, Linda Patrik, recognised the treatise’s tone and tipped off the FBI, which had been searching for the Unabomber for years in the nation’s longest and costliest manhunt.
Authorities in April 1996 found him in a 10-by-14-foot plywood and tarpaper cabin outside Lincoln, Montana, that was filled with journals, a coded diary, explosive ingredients and two completed bombs.
As an elusive criminal mastermind, the Unabomber won his share of sympathisers and comparisons to Daniel Boone, Edward Abbey and Henry David Thoreau.
But once revealed as a wild-eyed hermit with long hair and beard who weathered Montana winters in a one-room shack, Kaczynski struck many as more of a pathetic loner than romantic anti-hero.
Even in his own journals, Kaczynski came across as not a committed revolutionary, but a vengeful hermit driven by petty grievances.
“I certainly don’t claim to be an altruist or to be acting for the ‘good’ (whatever that is) of the human race,” he wrote on April 6, 1971. “I act merely from a desire for revenge.”
A psychiatrist who interviewed Kaczynski in prison diagnosed him as a paranoid schizophrenic.
“Mr Kaczynski’s delusions are mostly persecutory in nature,” Sally Johnson wrote in a 47-page report.
“The central themes involve his belief that he is being maligned and harassed by family members and modern society.”
Kaczynski hated the idea of being viewed as mentally ill and when his lawyers attempted to present an insanity defence, he tried to fire them. When that failed, he tried to hang himself with his underwear.
Kaczynski eventually pleaded guilty rather than let his defense team proceed with an insanity defense.
“I’m confident that I’m sane,” Kaczynski told Time magazine in 1999. “I don’t get delusions and so forth.”
The notorious criminal had spent the past two decades in a federal Supermax prison in Colorado and in 2021, he was moved to the US Bureau of Prison’s FMC Butner medical centre in eastern North Carolina.
Kaczynski skipped two grades to attend Harvard at age 16 and had published papers in prestigious mathematics journals.
His explosives were carefully tested and came in meticulously handcrafted wooden boxes sanded to remove possible fingerprints. Later bombs bore the signature “FC” for “Freedom Club.”
The FBI called him the “Unabomber” because his early targets seemed to be universities and airlines.
