A Michigan man with a history of bizarre rants and threats against the FBI was charged Thursday with trying to use an explosive to damage a federal building in downtown Detroit, authorities said.

Gary Mikulich, 42, is accused of leaving a metal cash box containing explosive components outside the Patrick V. McNamara Building, which houses the FBI, the Internal Revenue Service, immigration court and other agencies.

A tool bag holding the box was discovered Feb. 26 and brought inside the building, but it sat for 20 days before authorities destroyed it last week, the FBI said in a court filing.

The exploded materials included pieces of PVC pipe, a timer and black electrical tape, along with a handwritten note that read, “1. Turn Switch 2. Plug, in,” agent Mark Davidson wrote.

The FBI is not calling it a bomb; all pieces were being examined by experts, spokeswoman Sandra Berchtold said.

Mikulich lives in Kingsford in Michigan’s Upper Peninsula, about 500 miles northwest of Detroit. According to the affidavit, he has complained to the police about the FBI and what he called a “card system” more than a dozen times since January.

Mikulich was arrested Thursday and is due in federal court Friday in Marquette, also in the Upper Peninsula. An attorney has not been assigned.

— Associated Press