When ISIS beheaded two of Matthew VanDyke's friends, journalists James Foley and Steven Sotloff, he began to wonder what he could do to stop what he calls "this scourge on humanity."
That's why he is in Iraq now, preparing to train Christians there to defend themselves.
"I think if you believe in something, you should get out and do something about it rather than just give it a thumbs-up to the television from your sofa," he said.
So last year he founded Sons of Liberty International (SOLI), a security company that trains vulnerable populations to defend themselves against terrorists and insurgents.
In early May, VanDyke plans to begin another session of training at a secret location. The men are members of Nineveh Plain Protection Units (NPU), a military force in a primarily Christian region of Iraq where believers face extinction unless they can win the fight against the Islamic State in Iraq and Syria.
SOLI began working with the NPU in December 2014 and has trained the entire battalion of more than 300 men.
Unlike other security contractors, SOLI doesn't charge for its services; it operates on a non-profit business model and is dependent on financial contributions from the public for support.
VanDyke started Sons of Liberty International, named after the Revolutionary War era Sons of Liberty, with about $12,000 of his own money.
"The Christian community in Iraq has been pushed around for a long time, and it needs to stop, and I have the right connections and experience to be able to pull something together to help them, so that's what I'm doing," VanDyke said.