A former leader of the Ku Klux Klan who maintained a profile in the white supremacist movement even after leaving the organization, Mahon was once recorded by authorities bragging about carrying out numerous bombings throughout the nation since the early 1980s.
Authorities hailed his sentencing on Tuesday as a blow against racial hatred in America. The investigation was run by veteran U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives special agent Tristan Moreland, who tracked the white supremacist for years and arrested Mahon and his twin brother in 2009 at a house in rural Illinois.
"Today's sentence makes clear that such acts of violence will not be tolerated in Arizona," Thomas Atteberry, the special agent in charge of the ATF's Phoenix office, said in a written statement. "We will continue to use every tool in our arsenal to put criminal hatemongers on notice — no matter how long it takes — they are not beyond our reach."
At the sentencing, Mahon was unapologetic, According to the Associated Press, he said he couldn't apologize to the victims because "I didn't do this bombing."
Mahon was tried earlier this year alongside his twin brother, Daniel Mahon, who authorities also accused of helping in the bombing of Scottsdale's Office of Diversity and Dialogue. A jury, however, acquitted Daniel Mahon and he was set free.
The jury also ruled that the bombing was not a hate crime. Despite that, the AP reported, U.S. District Judge David Campbell called it an "act of domestic terrorism" during the sentencing.
Still, Campbell didn't completely side with prosecutors, either. The U.S. Attorney's Office in Phoenix asked last wek for Mahon to be sentenced to 63 years in prison.
According to authorities, Mahon at the time of his arrest was a follower of a hate group called the White Aryan Resistance, or WAR, which was run by one of the nation's best known white supremacist leaders, Tom Metzger.