BOSTON (CBSNewYork/AP) — One of the explosive devices used in the bombings of the Boston Marathon appeared to have been in a metal pressure cooker packed with nails and ball bearings, CBS News reported.
As CBS 2’s Lou Young reported, a law enforcement source told CBS News that one of the explosive devices appeared 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.
The two bombs that exploded were made to look like discarded property, a law enforcement official told CBS News. 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. This is consistent with doctors reporting shrapnel pulled from victims. The official said there were apparently things like BBs, ball bearings and nails in the bombs.
While no information has been released about whether the attack was domestic or international in nature, authorities have noted that the pressure cooker design for the bombs is favored by al-Qaeda.
Similar pressure-cooker explosives have been used in Afghanistan, India, Nepal and Pakistan, according to a July 2010 intelligence report by the FBI and Homeland Security. Also, one of the three devices used in the May 2010 Times Square attempted bombing was a pressure cooker, the report said.
“Placed carefully, such devices provide little or no indication of an impending attack,” the report said.
But since the other attacks, authorities noted, the design has been widely circulated and could have been picked up by an independent operator – a lone wolf.
The Pakistani Taliban, which claimed responsibility for the 2010 attempt in Times Square, has denied any role in the Boston Marathon attack.
Regardless, Suffolk County, Mass. District Attorney Daniel Conley said someone will pay for Monday’s attack.
“Make no mistake an act of cowardice and of this severity cannot be justified or explained. It can only be answered,” Conley said.
Meanwhile, police and federal agents appealed to the public Tuesday for amateur video and photos that might yield clues to the bombing as the chief FBI agent in Boston vowed to find whoever carried out the deadly attack.
There has to hundreds if not thousands,” said Massachusetts State Police Col. Timothy Alben. “I would urge you to bring everything, even if you think it’s not important.”
President Barack Obama, who will travel to Boston on Thursday, said the bombings were an act of terrorism, but investigators do not know if they were carried out by an international organization, domestic group or a “malevolent individual.” He said, “the American people refuse to be terrorized.”
On Capitol Hill, Defense Secretary Chuck Hagel called the bombings “a cruel act of terror” and said “a thorough investigation will have to determine whether it was planned or carried out by a terror group, foreign or domestic.”