Master Sgt. Matthew Livelsberger, an active duty Green Beret for almost 20 years, shot himself just before the truck exploded, police said.

Matthew Livelsberger mostly bore that burden in private but recently sought treatment for depression from the Army, according to a U.S. official.

Retired mixed marshal arts star Tim Kennedy said he was “flabbergasted” when he learned that Matthew Livelsberger is believed to be behind the Jan. 1 blast that injured 7.