The Washington Post published a 35,000-word manifesto written by the Unabomber, who since the late 1970s had eluded authorities while carrying out a series of bombings across the United States that killed 3 people and injured another 23.
After reading the manifesto, David Kaczynski's wife realized the writing style was similar to that of her brother-in-law, she convinced her husband to notify the F.B.I.
On April 3, 1996, Ted Kaczynski was arrested at his isolated cabin near Lincoln, Montana, where investigators found evidence linking him to the Unabomber crimes.
There is a great series on Netflix MANHUNT: THE UNABOMBER it is really good and explains just how little evidence the FBI really had on Ted.
Theodore John Kaczynski was born May 22, 1942, in Chicago. A talented math student, he entered Harvard University at age 16. In 1967, after receiving a Ph.D. in mathematics from the University of Michigan at Ann Arbor, Kaczynski was hired as an assistant professor at the University of California, Berkeley.
However, he resigned abruptly in 1969 and eventually began living as a hermit in a small Montana cabin that lacked electricity and running water. Kaczynski received occasional financial support from his family.
FBI agent Jim Fitzgerald who figured out the linguistics link to Unabomber
From 1978 to 1995, the Unabomber carried out 16 bombings and mail bombings across the U.S. and became the subject of a massive F.B.I. manhunt. The F.B.I. codenamed him UNABOM because his targets included universities and airlines. Over the years, his victims included professors, scientists, corporate executives, and a computer store owner, among others.
On September 19 of that year, after discussions with the F.B.I. and Attorney General Janet Reno, the Post, in collaboration with the Times, published the manifesto, which railed against industrialized society.