Authorities have arrested a Rockland County man, accusing him of planning to blow himself up in Washington, D.C., on Election Day.

FBI agents raided the Tappan home of 56-year-old Paul Rosenfeld on Wednesday. They say they found a 200-pound explosive in the basement of the home. Rosenfeld, authorities say, bought the bomb materials on the internet and built it in his basement.

Rosenfeld is charged with making and transporting a bomb. Authorities say he planned to use it to kill himself on the National Mall.

Authorities also say they found a series of letters and text messages sent in August and September that show Rosenfeld intended to detonate the device as a way to bring attention to his political beliefs.