“The bombs that turned the finish line at the Boston Marathon into a scene of horror were made from pressure cookers and hidden in backpacks, federal law enforcement sources said Tuesday.
The blasts were likely detonated by timers — not by cell phones, a law enforcement official said.
The U.S. government has warned federal agencies in the past that pressure cookers — airtight pots used to quickly cook or preserve foods — have been turned into bombs in parts of the world. A Department of Homeland Security memo called it ‘a technique commonly taught in Afghan terrorist training camps.'”
Source: Source: Bombs were likely in pressure cookers in backpacks – CNN.com