Theodore John Kaczynski aka the "Unabomber" is a former mathematics professor, a domestic terrorist, and serial killer who between 1978 and 1995 killed 3 and wounded 23 others by attempting to start a nationwide combing campaign targeting people involved with modern technology. 
Kaczynski was found dead in his cell on June 10, 2023. 
 
One page handwritten letter hand dated February 5, 2016 and hand signed twice.
The letter is written on the back of the first page of a five page letter which Kaczynski has included a complete copy of warning the recipient of this journalists tactics.
Kaczynski has hand signed at the top, Ted Kaczynsk and hand signed again at the close, Ted.