Austin, Texas — Police Chief Brian Manley, facing a phalanx of cameras and reporters, declared what residents in and around the Travis County neighborhood that seems to be the target area of the “Austin Bomber(s)” already were fearing.
“We are clearly dealing with a serial bomber.”
The latest improvised explosive device, or IED, to explode was in the Sunset Valley area of southwest Austin. The IED went off around 8:30 Central time after two young men were riding their bicycles on the road and according to Austin police along with San Antonio based Federal Bureau of Investigations (FBI) Special Agent in Charge(SAC) Christoper Combs. That this particular IED was “victim operated” by a trip wire or a “crush wire” that was strewn across the roadway to detonate the IED hidden near a fence just off the roadway.
Both victims, aged 22 and 23, are in stable condition at this time yet are suffering from “significant blast injuries.”
Combs said that this latest device is different from the other three with the use of a “crush wire” as the detonator and shows the FBI along with local law enforcement that the IED is , “more sophisticated, it’s not targeted to individuals … a child could be walking down a sidewalk and hit something.” He continued; “with this tripwire, this changes things.”
The U.S. military and service members having served or still serving in places like Iraq and Afghanistan are no strangers to these types of IED’s. They are known as “Victim-Operated Improvised Explosive Devices”, or VOIED‘s.
VOIED’s are simplistic in its construction, yet belies the actual sophistication it takes to develop, build, and deploy these devices. The bomb-maker must understand open versus closed loop circuit, proper handling or manufacturing of explosives, and design. And its clear this person or persons understand this all too well.
The basic construction of a simple “crush-wire” initiator is built with high conduction copper or steel wire separated by a form of non-conducting plastic that “gives” under any sort of weight. These trip wires can be constructed from a piece of wood with two metal strips or made with plastic tubing not unlike what you can find at pet stores for aquariums or at home improvement stores for home projects.
By design these types of initiators work with some sort of weight, be it a person or vehicle, which “crushes” or pinches the semi-pliable tubing lined with conductive or thin metal into one another. Thus, if the device has a power supply running through the wire and the two metal points touch. The charge of electricity is sent directly to the firing mechanism that was closed out of the loop by the tubing and the IED explodes.
According the the FBI SAC, a “trip wire” was strung across the road and the IED was possibly triggered by one of the two victims bicycle riding over the crush wire and caused the bomb to go off. Which is now leading the FBI bomb experts to think that the tactics of this serial bomber, or bombers is evolving.
The sophistication in the IED’s simplistic construction was reiterated by Chief Manley as he described the each bomb having a power source, simple and professional like wiring, and now the addition of trip wires.
The first three bombs were left on doorsteps of the bomber’s intended target and seemed to have been detonated by the victim by either tilting the package past a certain degree plane and thus possibly closing a circuit loop “switch” or opening the package and triggering the bomb that way.
And like all serial killers, the bomber is proud of his creations, which the FBI and local law enforcement alluded to the devices having a pattern or a personalized “signature” in the devices construction.
This latest IED bombing attack quite possibly shows that the bomber has more IED attacks planned and will be implementing all sorts of deadly versions of his “creations” and may be intent on surrounding the already terrorized city of Austin with more bombings.
Feature image courtesy of: Associated Press