A man accused of placing an explosive outside a federal building in Detroit has made strange complaints about the FBI, referred to himself as the president and blamed something called the "card system" for deaths in his northern Michigan community, authorities said.

Gary Mikulich, 42, has been charged with trying to use an explosive to damage the McNamara Federal Building and was scheduled to appear in court Friday, a day after his arrest about 500 miles from Detroit in Michigan's Upper Peninsula. The case has embarrassed the government because the explosive _ inside a metal cash box that was in a tool bag _ sat inside a building that houses the FBI, Internal Revenue Service, immigration court and other agencies for 20 days before authorities did anything with it.

According to an affidavit filed in court, Mikulich has complained to the police about the FBI and a so-called "card system" more than a dozen times since January. The complaints claim the "card system" has "led to the murder of thousands of people and has attacked him."

A Feb. 11 fax read: "This card system is going berserk for some reason. They are making threates of hitting the local police, sheriff's office, and state police. They are threatening to murder me too."

Mikulich, who has an electrical engineering degree and lives in Kingsford in Michigan's Upper Peninsula, referred to himself as "President Mikulich" and the "nominated president of the United States of America," the FBI said.

The agency doesn't "have any idea" what is meant by a "card system," FBI spokeswoman Sandra Berchtold said.

A tool bag holding the metal box was discovered outside the building on Feb. 26 and brought inside, authorities said. It sat until a Federal Protective Service officer decided to X-ray it on March 18, saw electrical components and summoned the Detroit police bomb squad, which blew it up miles away at a city park, the FBI said.

"We're all a little shaken," said Catherine Gase, 49, who works for the U.S. Small Business Administration. "I can't imagine how that could have happened. I can't imagine why we weren't evacuated. ... I was completely unaware of what was happening until the all-clear was announced."

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 in an affidavit filed in court.

The FBI is not calling it a bomb; all pieces are still being examined by experts, Berchtold said.

The Department of Homeland Security has suspended a contract security officer as it investigates why the bag and metal box sat inside the McNamara building for so long. The Federal Protective Service, which guards federal buildings, is also sending trainers to Detroit.

"It was put in a locked room, basically on the assumption that it was a lost-and-found issue. This violated all security protocols," said David Wright, president of the American Federation of Government Employees Local 918, which represents Federal Protective Service officers in Detroit but not the contract guards.

The FBI said it focused on Mikulich after learning that Home Depot is the exclusive seller of the Husky tool bag. The store in Iron Mountain, near his home, sold a bag and a timer at the same time on Feb. 14, one of only nine similar sales at all U.S. locations since last fall.

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Associated Press writer Corey Williams contributed to this story.