New York man built and planted bombs on Williamsburg Bridge and Manhattan rooftops, authorities say

A suspect plotted to place at least seven improvised explosives across New York City, including on a subway track on the Williamsburg Bridge and a Manhattan apartment rooftop, according to law enforcement.
Michael Gann, 55, of New York City, allegedly ordered chemicals that can be combined to make explosives, built seven devices and placed six of them before he was stopped by law enforcement.
According to the indictment, Gannโs alleged bombs were far more powerful than any legally-obtainable consumer explosive, containing โapproximately 30 grams of explosive powder, which is approximately 600 times the legal limit for consumer fireworks.โ
Police allegedly have surveillance footage showing Gann placing his devices on rooftops in Manhattan.
According to prosecutors, Gann ordered two pounds of potassium perchlorate, a pound of aluminum powder, more than 200 cardboard tubes, more than 50 feet of fuses, and other, unspecific items that can be used for bomb building on May 30.

Gann allegedly received the materials on June 4, and prosecutors say he tested them by combining the perchlorate and and aluminum powder to create an explosion. He then allegedly transported the materials to Manhattan and built the bombs. Five of the explosives were found on Manhattan rooftops, one was found on the subway tracks on the Williamsburg Bridge, and another was found, allegedly, on Gannโs person after his arrest.
He’s being charged with one count of attempted destruction of property by means of explosives, one count of transportation of explosive materials, and one count of unlawful possession of destructive devices.
If convicted, Gann will face a maximum penalty of 40 years in prison.