‘Unabomber’ Ted Kaczynski previously tried to hang himself — with his underwear

“Unabomber” Ted Kaczynski previously tried to kill himself in jail — by hanging himself by his own underwear.

The infamous convict — who killed himself at the federal medical prison in Butner, NC, on Saturday — carried out a 17-year bombing spree that killed three and injured 23 others before he was caught and sentenced to more than four life terms in May 1998.

But months before he even went to trial, Kaczynski tried to commit suicide after a failed bid to fire his lawyers.

He appeared in court hours afterward with the red marks from his hanging attempt still around his neck.

Then-Sacramento County Undersheriff Lou Blanas told reporters that the night before the court hearing Jan. 9, 1998, Kaczynski “attempted to hang himself with his own underwear,” the Tampa Bay Times reported at the time.

The suicide attempt was confirmed by family lawyer Anthony Bisceglie, who was representing Kaczynski’s brother, David, the man who turned him in after realizing his sibling was the infamous “Unabomber.”

The suicide attempt put the Harvard-educated math professor-turned hermit on suicide watch.

During the hearing, the suspect could be seen ignoring David and their mother, who were seated only a few feet from him. There was no mention of Kaczynski’s suicide attempt in court.

The failed attempt occurred after the court dismissed his request to fire his defense lawyers when they refused to toss out plans to claim Kaczynski was suffering from a mental illness.

More than 25 years later, on Saturday, officials said they found Kaczynski, 81, unresponsive inside his cell around 12:30 a.m.

He was revived with CPR but pronounced dead at a hospital later that morning, with multiple sources telling The Associated Press that he committed suicide.

The Chicago native had been moved from the federal supermax prison in Florence, Colo., to a medical facility in North Carolina in December 2021 because of ill health after being diagnosed with late-stage cancer.

Kaczynski was an Ivy League-educated math professor who left society to live in a cabin in Montana.

He is believed to have set off his first homemade explosive at a Chicago university in 1978.

He confessed to carrying out 16 bombings between 1978 and 1995 and was captured only after his brother recognized his handwriting in the infamous “Unabomber Manifesto,” a 35,000-word, anti-technology and anti-leftist writing that warned about mankind’s end from rapidly evolving tech.

After a massive manhunt, Kaczynski was captured by police in his small plywood and tarpaper cabin in the woods outside Lincoln, Mont.