Domestic terrorist 'Unabomber' Ted Kaczynski died by suicide in his federal prison cell, according to insiders familiar with the situation.

Kaczynski was found dead in his cell at around 8 a.m. in the Butner Federal Correctional Complex in North Carolina. He was 81 years old. 

While the formal cause of death has not been disclosed, sources say that he died by suicide, reports the New York Times.  

After shooting to infamy by executing 16 bombings over a 17-year reign of terror, Kaczynski was given life without the possibility of parole when he was finally caught in 1996.