Wednesday, a man admitted in Washington, DC, to making more than 12,000 unwanted phone calls to Congress members and threatening to kill a staff member of Congress. The Justice Department and US Capitol Police released the guilty plea Thursday.

35-year-old Ade Salim Lilly from New York was caught in Puerto Rico in November. He pleaded guilty Thursday to two charges, including making repeated phone calls and communicating with someone across state lines with a threat to kidnap or hurt them.

The people who were called were not named in court documents. The police say Lilly changed his phone number to get people in Congress to answer his calls.

The Justice Department said in a statement Thursday that most of these calls were taken by House staff or interns. “During some of these calls, Lilly got mad and used rude and annoying words to talk to the person who answered the phone.” Staff in Congress told Lilly over and over again not to call. There were several times when U.S. Capitol Police told Lilly that his phone calls were unwanted and illegal because they were annoying.

Authorities say Lilly told a staff member, “I will kill you, I will run you over, I will kill you with a bomb or grenade” in one call. During two days, he called one Congressman more than 500 times, says the government.