A man accused of building explosive devices and stashing them on Manhattan rooftops and the Williamsburg Bridge has been indicted on weapons-related charges, authorities say. Michael Gann allegedly made at least seven improved explosive devices (IEDs) using precursor chemicals — chemicals that can be combined into an explosive mixture — that he bought online.

A 55-year-old man was indicted Tuesday after creating and placing at least seven improvised explosive devices in different areas of New York City, including subway track on the Williamsburg Bridge and on a Manhattan rooftop,

Michael Gann also stored shotgun shells and at least five other improvised explosive devices on rooftops in SoHo, prosecutors said.