Austin police have announced a $50,000 reward for information leading to an arrest in connection with three bombings they believe are connected, and forensic experts say the investigation may zero in on details about the devices used and the victims targeted.
Following three incidents across the city in less than two weeks that have left two people dead and two seriously injured by explosive packages found outside their homes, Acting Austin Police Chief Brian Manley said Tuesday that the new reward is in addition to the $15,000 Texas Gov. Greg Abbott has already offered.
“We are not going to leave any stone unturned and we are going to follow up on every lead,” Manley told reporters.
The first explosion occurred on March 2 in the Harris Ridge neighborhood, killing 39-year-old Anthony Stephan House.
Early Monday morning, the second blast went off at a home about 12 miles away in east Austin. Draylen Mason, 17, was killed and his mother was hospitalized with potentially life-threatening injuries.
A few hours later, another package exploded in southeast Austin about five miles from the site of the second bomb, injuring a 75-year-old Hispanic woman who remained in critical condition Tuesday.
Authorities have revealed few specific details about the devices or why they are believed to be connected beyond that they were all in cardboard packages, but Manley said Monday they were made with “a certain level of skill.”
Explosives experts say parcel bombs can be more complicated to build than a simple pipe bomb because they need to be rigged to explode when opened.
“Most of the skill or sophistication in building bombs is based on how it is initiated,” said Adam Hall, a former forensic chemist for the Massachusetts State Police who is now director of the Core Mass Spectrometry Facility at Northeastern University’s Barnett Institute of Chemical and Biological Analysis.
However, he stressed that much of the information one needs to learn how to build such devices is available on the internet.
“Operating viable devices like we’ve seen in Austin, yes, those are difficult to make,” said Ben West, a global security analyst for Stratfor Threat Lens who has studied parcel bombs.
In addition to having a working trigger mechanism, the bombs had to be transported to the target locations without detonating. The bomber likely made many devices before to test their technique.
“This person is not an amateur,” West said.
Danny Defenbaugh, a Texas-based security consultant who worked for the FBI for 33 years and was lead investigator on the 1995 Oklahoma City bombing case, said a higher degree of proficiency is needed to construct a parcel bomb because it can be more dangerous than building other devices.
“I don’t know if it’s any more difficult,” he said. “It’s a little bit more ingenious in that it’s easier to kill or blow yourself up while making it.”
According to Manley, investigators believe the packages are being dropped off overnight rather than delivered by the U.S. Postal Service or any professional shipping service.
While it is not unusual for package bombs to be shipped through commercial carriers, the apparent hand-delivery could make them more difficult to trace. The post office or a service like Fed Ex or UPS would have shipping and tracking records and they might have information about the packages themselves.
“The fact that all three have exploded means we don’t really know what these devices looked like when they were delivered,” West said.
Shipping a bomb creates risks that the package will be flagged as suspicious before it reaches its destination. Dropping it off by hand at least ensures it reaches the correct address.
Police are also working to determine a motive. Though Manley has said there is no apparent link to terrorism, they have not ruled out a hate crime, since all of the victims have been black or Hispanic.
“We are not going to ignore the fact that the victims were all persons of color,” he said Tuesday.
A correlation between the victims could help identify the perpetrator, Defenbaugh said, and because a bomb like this requires an action by the recipient to detonate it, there usually is a specific target.
“Normally, those types of devices are built to attack a certain victim or certain target,” he said, though he added the intended target is not always the one who opens the package.
There is no clear connection between the three locations where the explosions occurred. House’s stepfather told the Washington Post he is good friends with the grandfather of the 17-year-old victim, but that is the only link that has been reported.
Experts say investigators will now likely be pursuing a few areas of inquiry to identify and build a case against a suspect.
“They’re going to be picking apart the bomb scenes looking for any small fragments that can help them reconstruct the device,” West said.
If they can determine the specific materials used to make the bomb, authorities can trace them back to the seller and find out who purchased them. The ATF and the FBI are already lending their expertise on explosives to assist with this.
According to Hall, forensic investigators are trained to look for specific components of the device that survive the explosion in some form and for items that seem foreign to the explosion site.
“Even after the explosion occurs, it’s not as if everything is gone…. They’re often looking for either heat-damaged or fire-damaged materials,” he said.
UPDATE: APD clarifies that they thought the initial explosion from 3/2 was an isolated incident because they "had a strong working theory" that the first explosion was retaliation for a raid on a nearby home and a case of mistaken identity.— MelanieTorre (@melanietorre) March 13, 2018
He cited the example of the Boston Marathon bombing in 2013, when search warrants were obtained after the suspects were identified and items similar to those found in the bombs were discovered in their home.
“Obviously, their primary concern is developing a suspect or suspects in order to then go to the court to get search warrants for their property, their vehicles, and their person,” he said.
According to Defenbaugh, figuring out how the device was constructed can tell investigators about the maker’s background, including whether they have military or intelligence training.
“The bomb-builder’s signature usually will make it so that you can positively identify an individual more readily or easily because of the resources and ingenuity used to make this kind of bomb,” he said.
While forensic scientists analyze evidence from the bombing scene, officers will be canvassing the area for witnesses or surveillance video that could point to a suspicious person or vehicle.
If the location of the purchase of bomb materials is determined, police can go to a store like Lowe’s or Home Depot and view security video or obtain credit card records.
A close family friend told me 17-year-old Draylen Mason was a happy-go-lucky young man with a bright future. He was a black belt, a teacher at a martial arts studio, and a talented musician. His life was cut short when a package bomb exploded yesterday at his home. @cbsaustin pic.twitter.com/r0UkjMBZQN— Sarah Navoy (@SarahNavoyCBS) March 13, 2018
In a September 2016 case, investigators tied Ahmad Khan Rahimi to bombings in the Chelsea neighborhood of Manhattan and Seaside Park, New Jersey in part through billing records that connected his family’s address to the cell phones used as detonators on the devices.
According to West, package bombs in general are less common in the U.S. than in some other countries.
“Around the world, it’s something we probably see on a near monthly basis,” he said. “European anarchists really love this tactic.”
Parcel bombs have been used in both personal and politically-motivated attacks, aimed at random and specific targets.
“It’s an effective terrorist tactic…. Lots of people are obviously and rightfully scared of what’s going on,” West said.
Suspects in previous high-profile U.S. bombing cases have been identified and arrested through various means, including bomb-makers’ errors, tips from the public, and luck.
An arrest affidavit for Rahimi for the Chelsea and Seaside Park explosions laid out an array of evidence, including eBay purchase records for bomb components, surveillance video, and social media postings. However, the initial identification of the suspect was made from a fingerprint on a third pressure cooker bomb that failed to detonate a few blocks from the Chelsea blast.
After the Boston Marathon bombing, the suspects were first located when an SUV they carjacked was tracked by a GPS anti-theft system. One of them was fatally wounded in the subsequent firefight and was identified as Tamerlan Tsarnaev at the hospital.
The second suspect was then identified as Dzhokhar Tsarnaev, Tamerlan’s brother. Following an intense citywide manhunt, Dzhokhar was found because a resident called 911 to report seeing him hiding in a winterized boat in his yard.
Unabomber Ted Kaczysnki evaded identification and arrest for 17 years as he mailed or planted 16 package bombs, killing three people and injuring 23. After the Washington Post published his 35,000-word manifesto in 1995, Kaczynski’s brother recognized it as his writing and made contact with the FBI.
The series of explosions in the last 11 days has left Austin residents understandably concerned. As of 5 p.m. Tuesday, police had received 265 calls about suspicious packages. None were determined to be dangerous, but police encourage the public to remain vigilant.
“I very much appreciate that the community has listened and you are bringing us your concerns and I would implore you to continue to do so,” Manley said.
West noted several telltale signs people should watch for if an unexpected package arrives at their door.
“If its misshapen, if its lumpy, if it has stains on it, excessive or no postage…anything that looks strange or out of place,” he said. “I think people have instincts that will tell them if something’s wrong.”
Defenbaugh also advised caution when dealing with packages, particularly those that arrive when you have not ordered anything.
“Many times, you’ve got to look at the wrapping, who its addressed to,” he said. The lack of a return address can also be a clue.
“No bomb builder wants the bomb to come back to them,” he said.
West also warned that past cases have given him little reason to believe the bombers will stop or that they will limit their attacks to Austin city limits. Nearby cities like Houston and San Antonio must remain on alert.
“They have a diminishing window between now and when they get caught, so I would definitely expect to see more as long as this person remains active,” he said.
Anyone with information related to the case is asked to call Crime Stoppers at 512-472-8477.