AUSTIN, Texas _ Two weeks after Austin had its first bombing attack, investigators thought they were close to their big break.
Two names had bubbled up from a huge list based on receipts for possible bomb-making equipment. Police watched the two men around the clock. They hoped to catch one or both going to a store to buy bomb-making items. Instead, they watched two Austinites carry out mundane tasks.
A new bombing on March 18 _ the city's fourth _ changed everything.
Brian Manley, then Austin's interim police chief, had been at the city's 24-hour command center, a gated bunker in East Austin, most of the day. He decided to meet his family at their favorite Italian restaurant for dinner. As he was midway through his chicken Parmesan, his phone rang. Two men had just been injured in a blast in Southwest Austin.
Will Grote and Colton Mathis, high school friends in their early 20s, had been biking in the Travis Country neighborhood when the bomb went off. Paramedics rushed both to the hospital with leg injuries from shrapnel. Grote was left with permanent nerve damage.
As Manley raced to the scene, investigators wondered whether the explosion could have been the work of a copycat. The bomber had not left a package on a doorstep but instead used a tripwire anchored by two white-on-red "Drive Like Your Kids Live Here" signs to detonate his bomb.
Hundreds of FBI and U.S Bureau of Alcohol, Tobacco, Firearms and Explosives agents had already been dispatched to work Operation Austin Bomb, including two specialized national response explosives teams. Austin was jammed with South by Southwest tourists, forcing agents to commute from far-flung suburban hotels.
Agents from the ATF combed the scene of the attack in Travis Country and determined that the latest device bore the same hallmarks as the other three _ a metal pipe and explosive powder encased in a PVC pipe and surrounded by shrapnel. It was powerful enough to blast through a wooden fence lining the street and leave a pool of blood on the sidewalk from one of its victims.
It was the first time the bomber had struck west of Interstate 35 and in a predominantly white neighborhood. That forced investigators to change their working theory that the bomber was targeting minority residents _ or anyone in particular.
"This is a jump in sophistication," recalled Chris Combs, special agent in charge for the FBI's San Antonio regional office. He has been with the agency for 23 years and assigned to national units dealing with terrorism and weapons of mass destruction. "This is a jump in lethality. And that concerned us greatly. That was a whole other situation _ he's raising his game and taking it to another level."
Investigators also realized that connections between the previous victims were just coincidence. The first victim, Anthony Stephan House, was connected to the second victim, Draylen Mason, who was killed 10 days later, through House's father-in-law. But they were all just family friends. A Mason found in property records on nearby Galindo Street had no connection to Draylen Mason or his family.
Even as the latest attack revealed new information about the bomber's apparently random attacks, it frustrated investigators.
They had focused hard on the possibility that one of two men they had been surveilling for a week was the bomber. But neither of the men had been anywhere near the site of the fourth attack.
"Everyone felt like we had good persons of interest based on the information we had, and to see that evaporate, there is a moment of defeat," Manley said.
"Everyone just dug back in and doubled down and worked that much harder because we recognized it wasn't going to stop. The need was even greater to keep digging."
