“The explosives used in the deadly Boston Marathon bombing were contained in 6-liter pressure cookers and hidden in black duffel bags on the ground, a person briefed on the investigation told The Associated Press on Tuesday.
One of the explosives contained shards of metal and ball bearings, and another contained nails, the person said.
These types of pressure cooker explosives have been used in Afghanistan, India, Nepal and Pakistan, according to a July 2010 joint FBI and Homeland Security intelligence report. One of the three devices used in the May 2010 Times Square attempted bombing was a pressure cooker, the intelligence report said.
“Placed carefully, such devices provide little or no indication of an impending attack,” the report said.
The Pakistani Taliban, which claimed responsibility for the 2010 attempt in Times Square, has denied any role in the Boston Marathon attack.
“A law enforcement source told CBS News senior investigative producer Pat Milton that one of the explosive devices appears to have been placed in a metal pressure cooker … which had been placed in a black nylon bag or backpack. Investigators also found pieces of an electronic circuit board possibly indicating a timer was used in the detonation of the bomb.
A law enforcement official told CBS News that the two bombs that exploded were made to look like discarded property. It is still unknown if one or both bombs were in garbage cans. One may have been on the sidewalk.
The bombs were described as “low explosive,” but with “anti-personnel” packing. The official said there were apparently things like BB’s, ball bearings and nails in the bombs.
Law enforcement sources told CBS News’ Milton that a Saudi Arabian man who was being questioned by investigators is not being considered a suspect at this time, and it appears that he was a spectator who was injured in the attack.