​Almanac: The Unabomber

And now a page from our "Sunday Morning" Almanac: April 3rd, 1996, 20 years ago today ... the day the FBI arrested Theodore Kaczynski, the suspected Unabomber, at his cabin in rural Montana.

Beginning in 1978, a mysterious series of bombings across the country had killed three people and wounded 23 others.

A handwritten rough draft of the Unabomber's manifesto, which was eventually published in the Washington Post. AP

The targets were mostly either universities or airlines, which explains the origin his nickname: the "Unabomber."

For years, the only clue to his identity was a single sketch of a shadowy, hooded figure.

The big break came in 1995, when The Washington Post printed a long, anti-technology manifesto from the Unabomber entitled "Industrial Society and its Future."

Its ramblings reminded an upstate New York man named David Kaczynski of the kinds of things his older brother, Theodore, had written in the past.

Once a brilliant math student at Harvard, Theodore Kaczynski had long since abandoned academia to live as a recluse in that remote Montana cabin.

David Kaczynski's suspicions forced him to wrestle with a moral dilemma, as he told our Erin Moriarty back in 2005:

Ted Kaczynski in 1996. AP

"Because of the death penalty, the likelihood would be that I would either have some innocent person's blood on my hands if I did nothing, or my own brother's blood on my hands if I stepped forward," he said.

David Kaczynski DID step forward. He provided information that led to his brother's arrest and conviction.

And with top legal aid, David was able to help his brother to escape the death penalty, with a plea agreement.

Instead, Theodore Kaczynski is currently serving four life sentences without parole at the so-called Supermax prison in Colorado.

On May 22nd, he will be 74 years old.