Updated

An employee planted a working pipe bomb in the lighting department of a suburban Home Depot as part of a plot to extort $2 million from the company, a federal prosecutor said Thursday.

Daniel Sheehan, 50, of Deer Park, was arrested Wednesday and charged with attempted extortion and the use of a destructive device.

In an anonymous letter, Sheehan notified the manager of the Home Depot in Huntington that he had placed a bomb there, and police were able to find it, U.S. Attorney Loretta Lynch said. They took it away and detonated it, she said.

But Sheehan's letter said he only wanted to prove he could plant a bomb without being detected, Lynch said. He then threatened to set off three more bombs at Home Depots on Long Island if he didn't get the money, the prosecutor said.

The letter said those bombs would shut down the stores on Black Friday, the big shopping day after Thanksgiving, Lynch said. Each would hold a pound of roofing nails, according to the complaint.

After a second letter was sent, lowering the ransom demand to $1 million and setting a drop date for Oct. 26, investigators were able to identify and arrest Sheehan, Lynch said.

"Sheehan put lives at risk and tried to hold the people of Long Island hostage to his extortionate demands," Lynch said. "There is no bargaining to be had with human life, and the only payout Sheehan will receive will be the full measure of justice for his actions."

Sheehan was to be arraigned later Thursday at the federal courthouse in Central Islip. Lynch's office said he didn't yet have a lawyer.

If convicted, he would face a mandatory minimum sentence of 30 years in prison.