Report details how marathon bombs were made
BOSTON (WHDH) -- NBC News obtained a copy of a detailed government analysis of how the bombs in the Boston Marathon bombings were made.
Investigators have studied the remnants of the two bombs, which exploded near the finish line of the marathon on April 15. The bombs killed three people and injured more than 200.
The report says an explosive powder was inside those devices. The powder was most likely taken from commercial fireworks.
7News does know Tamerlan Tsarnaev, the older suspect killed last Thursday, had purchased powerful fireworks from a New Hampshire store earlier this year.
The report also says investigators continue to study the pressuer cooker bombs. They haven’t yet determined exactly how the devices were put together. But the report states small BB’s and nails were inside. They were attached to cardboard with some sort of epoxy.
The report also looked at the pipe bombs tossed from the suspects’ car as police chased them through Watertown. The government report says the bombs used elbow pipe, which is considered rare, but has been written about in extremist literature.
Investigators believe the Tsarnaev brothers got their bomb-making instructions from a magazine tied to the al-Qaeda terror network.