A Tennessee man was arrested Friday for allegedly making death threats against U.S. Sen. Mazie Hirono and U.S. Rep. Tulsi Gabbard.

Keahiokahouna Stewart, 36, was arrested by the FBI and U.S. Capitol Police after sending threatening emails and posting menacing videos to his Instagram accounts from August to September, according to the U.S. Department of Justice.

The complaint states that Stewart said in a recent Instagram post that he planned to travel to Honolulu from his home in Murfreesboro, Tennessee, on Nov. 1 with an AR-15 assault rifle and two handguns.

His plan was to kill people at the Prince Jonah Kuhio Kalanianaole Federal Building, including Hirono and Gabbard. The complaint notes that he had already purchased a plane ticket.

Officials had been keeping an eye on Stewart since 2013 after he began sending numerous complaints to federal officials, including Hirono and Gabbard, about his Social Security number and demanding payment of $50 billion.

In May 2015, he paid a visit to Hirono’s office in Washington, D.C., which resulted in a call to Capitol Police.

Stewart now faces charges of threatening to murder a U.S. official, which carries a penalty of up to 10 years in prison, and communicating threats through interstate commerce, which carries a sentence of up to five years.

This is at least the second time someone has been arrested for threatening Gabbard. Aniruddha Sherbow was detained in 2013 after telling her that he was going to cut off her head.