Police found a huge stash of guns and ammunition in his home, leading prosecutors to believe he was planning a "mass casualty" event.

Jeffrey Michael Kelly, 60, allegedly fired gunshots at the glass front door and a window of an Arizona Democrats' field office.

The suspect was also arrested for allegedly hanging suspicious bags of white power from political signs lined with razor blades.

Authorities in Arizona say a man arrested in shootings targeting Democratic campaign offices near Phoenix had more than 120 guns and apparently had been plotting a mass casualty event.

Arizona investigators surveilling the man accused of shooting at the Democratic National Committee office in a suburb of Phoenix saw him posting political signs with bags of a white, powdery substance attached,

Police investigating a series of shootings a Democratic National Committee office in Arizona found more than 120 guns, 250,000 rounds of ammunition and a grenade launcher at the home of a suspect, according to the local attorney’s office.