The ingenuity of the twin Boston Marathon explosions will offer important clues to investigators trying to solve the case, a former FBI bomb technician told Yahoo News Tuesday.
It matters “how they placed their tape or insulators, all the way down to how they tie the wires together,” said Danny Defenbaugh, the retired special agent who led the 1995 Oklahoma City bombing probe.
A team of specialized investigators has been dispatched to the race finish-line area in Boston where scores of victims were maimed by flying shrapnel when the two improvised explosive devices were detonated seconds apart.
Defenbaugh said the agents will try to recover the blasting accessories and other components so they can reconstruct the devices.
“Many times how the bomb was constructed will lead to a bomb’s signature and maybe identify a group or sometimes an actual individual who committed the crime,” said Defenbaugh, who supervised more than 150 bomb investigations during his 33-year career.
It was a vehicle identification number from a charred Ryder moving truck that helped the FBI quickly trace the Oklahoma City bombing to Timothy McVeigh and Terry Nichols. The pair had rented the truck and packed it full of explosives before killing 168 people and injuring at least 680 at the Alfred P. Murrah Federal Building in Oklahoma City on April 19, 1995.
“We have to be very, very careful and allow the evidence to point the direction,” he said.
Defenbaugh cautioned any pundits who may be painting the Boston bombs as unsophisticated.
“If you construct it, and it blows up as designed and explodes and you haven’t killed yourself, then it is pretty sophisticated,” he said.
The deadly Boston bombs were contained in 6-liter pressure cookers and hidden in black duffel bags on the ground, the Associated Press reported Tuesday afternoon. Pressure cookers have been recovered in foreign and domestic terrorist activity in recent years. An IED fashioned from a pressure cooker was found after the failed attempt to set off a bomb in Times Square in May 2010.
Boston Police Commissioner Eric Davis said Tuesday morning that the suspect is not believed to be among the dead.
“The three deceased are all victims as far as I know,” Davis said.
A European security official told the Associated Press on Tuesday that the initial evidence strongly suggests the culprits were not suicide bombers.
"So far, investigators believe it was not the work of suicide bombers, but it is still too early to rule it out completely," said the official, who spoke from the United States on condition of anonymity because he was not authorized to speak about the U.S. investigation.
Defenbaugh warned about eliminating suspects too early.
“It was undoubtedly a terrorist attack, however I’d be very careful in trying to subcategorize it as international or domestic,” he said. “History has proven that’s just not wise.”