WASHINGTON (AP) -- In kitchens, they prepare food faster, but pressure cookers by their very nature help make good bombs, amplifying the blast and the carnage.
They don't just hold the explosives. The tightly sealed pot makes easier-to-obtain but weaker explosives faster and stronger. And they may also help investigators find out who built the deadly homemade bombs that exploded at the Boston Marathon on Monday.
Investigators found fragments of BBs and nails, possibly contained in a pressure cooker, said Richard DesLauriers, the FBI agent in charge in Boston. He said the items were sent for analysis.
The pressure cookers are a key first piece in a painstaking detective process.
If the brand is determined, "investigators will track every store that sells that pressure cooker and when it was built and sold," Matthew Horace, a former special agent for the Bureau of Alcohol Tobacco, Firearms and Explosives, said.
The pressure cooker can also help point to the type of explosive, Denny Kline, a former FBI explosives expert, said.