AUSTIN — The explosion in an Austin neighborhood Sunday night had “similarities” with the three bombs that detonated in the Texas capital earlier this month, leading authorities to determine that they are dealing with a “serial bomber” terrorizing the city, police said Monday.
The latest blast, which injured two men who were walking along the road in a residential area, plunged the city further into a frightening mystery that has forced residents to remain locked in their homes as investigators scoured the area for answers.
The explosion on Sunday night was apparently set off by a tripwire on the road, leading police to believe the bomber or bombers had “a higher level of sophistication, a higher level of skill” than authorities initially believed, said Brian Manley, the interim Austin police chief. He also said this explosion marked an apparent shift in tactics after the three previous devices were left at people’s homes.
“What we have seen now is a significant change from what appeared to be three very targeted attacks to what was, last night, an attack that would have hit a random victim that happened to walk by,” Manley said. “So we’ve definitely seen a change in the method that this suspect … is using.”
The explosive device Sunday adds to the uncertainty and tension in Austin, which has been on edge since previous bombings killed two people and injured two others, one seriously. Authorities have seemed at a loss to explain who could be setting off these devices or why, saying only that the bombs were sophisticated and that the attacks could have been motivated by racial bias, although they acknowledged that this is only a theory.
This latest explosion injured two white men in their early 20s walking through part of Austin’s southwest area. Although the previous blasts all involved packages left at homes, this explosive was on the side of the road, Manley said.
The first two bombs killed black people — a 39-year-old construction worker and a 17-year-old high school student — related to prominent members of Austin’s African American community who were also close friends. The third bomb seriously injured a 75-year-old Hispanic woman, but it was addressed to a different home and apparently exploded when she was carrying it, said two people familiar with the case.
The first three explosions detonated in the eastern part of Austin, affecting areas where black and Hispanic residents live. Some in the area questioned whether the initial blast would have prompted more urgency had it gone off in a more affluent, predominantly white neighborhood.
This fourth explosion went off in the southwestern part of the city, far from the first three, and police said Monday that the two men injured are white. They were taken to a hospital with serious but non-life-threatening injuries, officials said, and hospital officials said they were in good condition.
Police said they are still considering whether some of the bombings were hate crimes.
“We’ve said from the beginning that we’re not willing to rule anything out, just because when you rule something out you limit your focus,” Manley said in an interview Monday with ABC’s “Good Morning America.” “This does change the concerns that we had initially, although we have still not yet ruled it out until we understand what the ideology or motive is behind the suspect or suspects.”
Manley said that police do not have evidence leading them to a particular suspect, and he reiterated his plea to the public for tips and information.
Authorities have described the explosives as the sophisticated work of a person or people who know what they are doing, saying that the bombers have been able to assemble and deliver these packages without setting them off.
Austin Mayor Steve Adler said that although the initial concern after the first bombings focused on packages left on doorsteps, Sunday night’s explosion caused officials to cast a wider net.
“We understand the anxiousness that we all feel, but there is just an army of law enforcement personnel working on this at this point,” he said Monday in a telephone interview with The Washington Post.
Adler said that “with each additional event, the horrible part is that people are getting hurt.” But, he added, “it also means that law enforcement folks get additional forensic evidence.”
The fourth explosion went off just hours after the Austin police made a public appeal in the case, increasing the reward for information to $100,000 and addressing the bomber or bombers in particular.
“These events in Austin have garnered worldwide attention,” Manley said during the earlier announcement. “And we assure you that we are listening. We want to understand what brought you to this point, and we want to listen to you.”
After Sunday’s explosion, Manley urged residents in the surrounding neighborhood to remain in their homes while investigators continue to search the area. Because of the darkness, he said, police may not know until after sunrise whether other suspicious devices were left in the neighborhood. He said that people who needed to leave their homes should call 911 for an escort.
“Given the darkness, we have not really had the opportunity to really look at this blast site to determine what has happened,” Manley said at a news conference late Sunday. “It’s obvious there’s been an explosion; it’s obvious it caused significant injures to two people, and it is important right now for anyone in the neighborhood behind us to remain inside and give us time to work through this.”
Manley also said that officers were working to clear a backpack left in the area. The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives were also on the scene, and Manley said that more than 500 officers have followed up on 435 leads and have conducted 236 interviews.
Steve Brown, 53, had gone out to dinner Sunday and was returning home when he saw the police tape.
“It’s kind of surreal,” he told The Post. “It had been on the other side of town — now it’s on our street.”
He said his 80-year-old mother-in-law was at home and told them she heard a “boom.”
Early Monday, the Austin Independent School District announced on Facebook that it was keeping school buses out of the neighborhood and would be excusing any related tardiness or absences. Regents School of Austin, a private Christian school near the neighborhood where the explosive went off, said classes would begin later Monday before ultimately canceling school.
After the first explosion on March 2 killed Anthony Stephan House, police initially described it as an isolated incident. However, when two more bombs exploded 10 days later, police said they thought all three were related.
The first blast on March 12 killed Draylen Mason, a high school senior well known for his love of music, playing everything from funk to mariachi to classical music. The second bomb that day critically wounded Esperanza Herrera, who was visiting her mother’s house, where the package was delivered.
At least two of the victims of the bombings have had a connection, although its significance was not immediately clear. House’s stepfather, Freddie Dixon, told The Post last week that he is close to Mason’s grandfather, Norman Mason. They were fraternity brothers, and Norman Mason also attended the church where Dixon was once a pastor, Dixon said.
Dixon said he did not think the connection was a coincidence.
“Somebody’s done their homework on both of us, and they knew what they were doing,” he said, adding that he believed the explosions were possibly a hate crime or the result of a vendetta.
Authorities have said they do not think the bombings were connected to the South by Southwest festival, although fears from these explosions creeped into the event, with a bomb threat forcing the Roots to cancel a concert Saturday night. Police said they arrested Trevor Weldon Ingram, 26, in connection with that threat.