In a Sacramento, California, courtroom, Theodore J. Kaczynski pleads guilty to all federal charges against him, acknowledging his responsibility for a 17-year campaign of package bombings attributed to the “Unabomber.”

Born in 1942, Kaczynski attended Harvard University and received a PhD in mathematics from the University of Michigan. He worked as an assistant mathematics professor at the University of California at Berkeley, but abruptly quit in 1969. In the early 1970s, Kaczynski began living as a recluse in western Montana, in a 10-by-12 foot cabin without heat, electricity or running water. From this isolated location, he began the bombing campaign that would kill three people and injure more than 20 others.

The primary targets were universities, but he also placed a bomb on an American Airlines flight in 1979 and sent one to the home of the president of United Airlines in 1980. After federal investigators set up the UNABOM Task Force (the name came from the words “university and airline bombing”), the media dubbed the culprit the “Unabomber.” The bombs left little physical evidence, and the only eyewitness found in the case could describe the suspect only as a man in hooded sweatshirt and sunglasses (depicted in an infamous 1987 police sketch).

READ MORE: Why It Took 17 Years to Catch the Unabomber

In 1995, the Washington Post (in collaboration with the New York Times) published a 35,000-word anti-technology manifesto written by a person claiming to be the Unabomber. Recognizing elements of his brother’s writings, David Kaczynski went to authorities with his suspicions, and Ted Kaczynski was arrested in April 1996. In his cabin, federal investigators found ample evidence linking him to the bombings, including bomb parts, journal entries and drafts of the manifesto.

Kaczynski was arraigned in Sacramento and charged with bombings in 1985, 1993 and 1995 that killed two people and maimed two others. (A bombing in New Jersey in 1994 also resulted in the victim’s death.) Despite his lawyers’ efforts, Kaczynski rejected an insanity plea. After attempting suicide in his jail cell in early 1998, Kaczynski appealed to U.S. District Judge Garland Burrell Jr. to allow him to represent himself, and agreed to undergo psychiatric evaluation. A court-appointed psychiatrist diagnosed paranoid schizophrenia, and Judge Burrell ruled that Kaczynski could not defend himself. The psychiatrist’s verdict helped prosecutors and defense reach a plea bargain, which allowed prosecutors to avoid arguing for the death penalty for a mentally ill defendant.

On January 22, 1998, Kaczynski accepted a sentence of life in prison without the possibility of parole in return for a plea of guilty to all federal charges; he also gave up the right to appeal any rulings in the case. Though Kaczynski later attempted to withdraw his guilty plea, arguing that it had been involuntary, Judge Burrell denied the request, and a federal appeals court upheld the ruling. Kaczynski was remanded to a maximum-security prison in Colorado, where he is serving his life sentence.