Friday, March 7, 2014
The Associated Press
(Continued from page 1)
Investigators in haz-mat suits examine the scene of the second bombing on Boylston Street in Boston Tuesday, April 16, 2013 near the finish line of the 2013 Boston Marathon, a day after two blasts killed three and injured over 170 people. (AP Photo/Elise Amendola)
Take the pressure cooker. If the brand is determined, "investigators will track every store that sells that pressure cooker and when it was built and sold," Horace said. "This kind of investigation requires hundreds, if not thousands of leads to be followed up on."
Horace and others are confident that the pressure cooker identification can be a big help.
The pressure cooker can also help point to the type of explosive, Kline said. If it's a high powered explosive like dynamite or C4, the blast would have shattered the cooker leaving sharp edges. If it's the low explosive, it will merely blast through, leaving more squared off edges, he said.
Once everything is pieced together, investigators will look for the "signature" or style of a bomber. Often — but less so since the Internet was born — a signature can lead to a bomber, Kline said.
"It's like a piano player," Kline said. "You can give Dave Brubeck or Chopin the same piece of music and it will sound different."
With this type of bomb, it can be triggered with something as simple as an egg timer or alarm clock, Parker said. Experts doubt a cellphone was used.
The use of nails, shards of metals and ball bearings also amplifies the personal devastation, experts said.
"We've removed BBs and we've removed nails from kids. One of the sickest things for me was just to see nails sticking out of a little girl's body," said Dr. David Mooney, trauma chief at Boston Children's Hospital, which treated 10 blast victims.