On September 19, 1995, a manifesto by the Unabomber, an anti-technology terrorist, is published by The New York Times and Washington Post in the hope that someone will recognize the person who, for 17 years, had been sending homemade bombs through the mail that had killed and maimed innocent people around the United States. After reading the manifesto, David Kaczynski linked the writing style to that of his older brother Ted, who was later convicted of the attacks and sentenced to life in prison without parole. All told, the Unabomber was responsible for murdering three people and injuring another 23.

Theodore John Kaczynski was born May 22, 1942, in Evergreen Park, Illinois, a Chicago suburb. As a student, he excelled at math, graduated from Harvard and received a Ph.D. in math from the University of Michigan. In 1967, he got a teaching job at the University of California at Berkeley, but quit two years later. In 1971, Kaczynski purchased some property in Lincoln, Montana, with his brother. There, the future Unabomber built a small, secluded cabin where he lived off the land as a recluse from the late 1970s until his arrest on April 3, 1996.

In May 1978, an un-mailed package was found in a University of Illinois, Chicago, parking lot; a security guard was later injured when he opened the package. The following year, another bomb exploded at Northwestern University, in Evanston, Illinois, injuring one person. In November of that same year, 12 people on an American Airlines flight from Chicago to Washington, D.C., were treated for smoke inhalation when a bomb in a mailbag aboard the plane caught fire.

Investigators eventually linked the three incidents, as the bombings continued and spread around the country. In December 1985, the owner of a computer store in Sacramento, California, was killed by a bomb filled with nail fragments. After a similar explosion in Salt Lake City two years later, investigators got their first eyewitness description of the bomber after someone reported seeing a man in aviator sunglasses and a hooded sweatshirt at the scene of the crime. In April 1995, The New York Times received a letter from the Unabomber stating that the killings would stop if the paper printed a 35,000-word manifesto. In September of that year, the Times and the Post complied, and David Kaczynski eventually recognized his brother Ted’s writing as that of the Unabomber and contacted the FBI.

In January 1998, Kaczynski agreed to a plea bargain with the government and was sentenced to four life sentences plus 30 years. He died in his cell and was pronounced dead on June 10, 2023 at the age of 81.