(CNN) — 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, officials said.
Investigators in Tempe began surveilling John Michael Kelly, 60, as a suspect in three separate shootings of the DNC office after receiving tips from the public, Tempe Police Chief Kenneth McCoy said at a news conference Wednesday.
They watched Kelly placing the signs with the bags attached from late Monday into Tuesday morning, the chief said.
Kelly was arrested Tuesday and is being held on three felony counts of acts of terrorism and four other counts related to the shootings.
He is being held on a $500,000 cash bond and will be subject to electronic monitoring if he’s able to post that amount, Maricopa County Attorney Rachel Mitchell said at the news conference.
Kelly may face additional charges related to the powdery substance, McCoy said. It was not immediately known what the substance was.