Explosive Devices Not Suspicious And Are Designed To Inflict Maximum Damage

NEW YORK (CBSNewYork) — CBS 2 has learned new details about the type of bombs used in the deadly Boston Marathon blasts. They had nails inside and that’s not all.

Investigative reporter Tamara Leitner has learned that police believe at least one of the bombs was placed in a metal pressure cooker with a locking lid.

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There are several reasons why this may have been used. It’s a common kitchen item and doesn’t appear suspicious. Pressure cooker bombs are also fairly simple to make. And when the bomb explodes, the metal pot becomes shrapnel.

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In the foiled Times Square bombing attempt in 2010, the terror plot at Fort Hood and Monday’s attack in Boston, the terrorist used a pressure cooker to conceal the bomb.

What's left of one of the bombs that exploded at the Boston Marathon on April 15, 2013. (Photo: FBI)

What’s left of one of the bombs that exploded at the Boston Marathon on April 15, 2013. (Photo: FBI)

“It was meant to do significant damage and meant to cause significant casualties,” former ATF agent Matthew Horrace told CBS 2’s Leitner.

Horrace said he believes the person or people involved in Boston’s massacre intended to kill many.

“We know right away they were very, very violent explosions with lots of blast force,” Horrace said.

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Sources told CBS News the bombs were made with low-order explosives, which cause a large boom and also cause the blast pressure to build and disperse slowly but intensely. This information could help investigators track down the bomb maker.

When asked if the powder is actually a calling card as to who made the bomb, Horrace said, “It could be. What we’ve seen in a lot of explosions throughout the years and a lot of the bombings, the bombers use a combination of high explosives and low explosives, black powder and smokeless powder, and there are different signatures for the different individuals involved.”

The number of injured from Monday’s bombs continue to grow and at least one doctor treating those patients reported pulling nail-like items and pellets from some of the wounded. Experts said the bombs contained shrapnel — likely BBs or ball bearings and nails.

“The only purpose to put shrapnel inside a device is to injure people and more people,” Horrace said.

Another challenge for investigators is some if not many of the items used in these bombs are common household items.

“Every bit of evidence will go towards trying to build that story and figure out who is responsible for making the device, where the items were that supported making the device and where these things were purchased,” Horrace said.

According to Department of Homeland Security experts, fighters are taught in Afghan terrorist training camps to use pressure cookers to hold bombs, because they are very common in that country and don’t draw attention when left in the open.

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