'Unabomber' Ted Kaczynski has died in federal prison

The man known as the "Unabomber," Theodore "Ted" Kaczynski was found dead in his North Carolina prison cell Saturday morning at age 81.

Officials with the Bureau of Prisons confirmed his death to the Associated Press and ABC News. He was found dead at about 8 a.m. A cause of death was not immediately known. 

He was serving a life sentence after sending by mail a series of homemade bombs around the country, including one that went off on an American Airlines flight, between 1978 and 1995. He pleaded guilty to setting 16 explosions that killed three people and injured 23 others.

Kaczynski had been transferred from a Supermax prison in Colorado to a federal prison medical facility in North Carolina in December 2021. Officials didn't say why he was moved at the time.

Contributing: The Associated Press