AUSTIN, Texas _ As a string of bombings continued Tuesday near the Texas capital, authorities recovered what could be the first crucial break in the case _ an intact package containing an explosive device that may have been sent out for delivery by a suspected serial bomber.
The package was retrieved by authorities after an early-morning explosion at a FedEx facility 60 miles south of Austin, the fifth in a series of bombings this month that have left two people dead, four others injured and rattled a city known for its urban cool.
Late Tuesday, somebody set off a device in a donation box at a Goodwill store in southern Austin, seriously injuring a man in his 30s, authorities said.
The Austin Police Department said on Twitter that it was not a bomb but an incendiary device, and that authorities had no reason to believe the incident was related to the package bombs. Designed to start fires, incendiary devices do not explode but release their energy more slowly.
Scott Stewart, a former investigator for the U.S. State Department and now a vice president of a global security firm, said the discovery of the intact package could be a "gold mine" for investigators. Even a sophisticated explosives expert, he said, could leave behind telltale signs such as hair and fibers while assembling a device.
The tactics in the bombings have shifted since the first explosion. Initially the bombs were left on front porches, then alongside a roadway with a tripwire attached, then shipped through FedEx. The explosion early Tuesday occurred as the package was being moved along a conveyor belt, being readied for delivery.
The bombings have reverberated across the nation.
"This is obviously a very, very sick individual, or maybe individuals ... and we will get to the bottom of it," President Donald Trump said from the White House.
Rep. Michael McCaul, a Republican from Texas, said the latest incidents could provide investigators with significant new evidence such as fingerprints and surveillance photos, which might lead to an arrest.
"This is terrorizing the city of Austin right now," McCaul said, calling the serial bombing inquiry "probably the biggest investigation since the Boston bombings."
White House Press Secretary Sarah Huckabee Sanders said on Twitter that "there is no apparent nexus to terrorism at this time."
The package that exploded Tuesday was apparently bound for an address in Austin. It detonated shortly after midnight at a facility in Schertz, located between the capital and San Antonio.
Federal investigators said on Twitter that the two packages located Tuesday were connected to the previous four devices, whose components were similar, linking the attacks.
"The safety of the employees and the public has been and remains our principal focus," Schertz Mayor Michael Carpenter said at a briefing with investigators outside the FedEx facility.
Schertz Police Chief Michael Hansen said local police, San Antonio bomb units, and agents from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives responded to reports of an explosion at 12:25 a.m. An employee standing near the conveyor was treated and released after complaining of ringing in her ears, he said.
"We're confident that neither this facility nor any in the Schertz area was a target," he said.
Experts theorize the bombings are the work of a local man, perhaps someone with military or law enforcement experience handling explosives, who has grown so brazen that he may have left key evidence behind, especially in the unexploded device recovered Tuesday.
"In many cases there will be a layoff, give it time to cool off after you attack. This guy has kept up the tempo," Stewart said. "That tells me he thinks he's better than the police."
Stewart said he worried the bomber's familiarity with explosives could lead him to plant new kinds of bombs, such as pressure plates or sticky bombs that can be attached to the underside of cars.
It took 17 years for authorities to catch "Unabomber" Theodore Kaczynski, but that was before fingerprint and DNA databases expanded and government agencies began amassing biometric data from things such as passports, Stewart said.
Security cameras and cellphone towers have also proliferated, increasing the chances that investigators can grab an image of whoever dropped the package off at the FedEx facility that they can release to the public.
Sunset Valley Police Lt. Rich Andreucci said the FBI contacted his office just south of Austin at 6:15 a.m. about securing the FedEx store in a strip mall there.
"The FBI believes the package in Schertz may have originated at this location," he said as he stood outside the police tape Tuesday.
Rep. Lloyd Doggett, D-Texas, who was briefed by authorities, said he was told that the second package was recovered intact from a FedEx facility near the airport in Austin. "They're trying to figure out how to open the package without destroying it," he said.
Federal investigators have said the serial bombings are a national priority that have drawn 500 federal agents, support from national forensic labs in Quantico, Va., and the attention of the president.
Austin Police Chief Brian Manley told City Council members at a meeting Tuesday that investigators have been sending evidence to the ATF, which is reconstructing the devices to determine what type of explosive charges were used.
"I cannot sit here and tell you whether there will be another incident. Based on the information we have, there is no reason to believe there will not," he said.
Three of the previous explosive devices were hidden in packages delivered to homes in residential neighborhoods on the east side of Austin. But the fourth, which detonated late Sunday in southwest Austin, injuring two bicyclists, was triggered by a tripwire, showing what the police chief called "a higher level of sophistication."
Manley said it wasn't clear whether an individual or group committed the attacks. He has tried to reach out to whoever is responsible, asking for a dialogue to prevent further harm to residents. But hours after the Austin police made a public appeal in the case Sunday, increasing the reward for information to $115,000, the fourth explosion occurred. The motive for the attacks also remains unclear, Manley said.
Anthony Stephan House, a 39-year-old construction worker, was killed March 2. Draylen Mason, a 17-year-old high school student, was killed March 12 in an explosion that injured his mother. Hours later, a third device exploded, injuring 75-year-old Esperanza Herrera.
Sunday's explosion injured white men bicycling through a wealthy neighborhood in southwest Austin, miles across town from the previous attacks. The two victims, identified by a friend and relative as former high school classmates Will Grote, 22, and Colton Mathis, 23, were in good condition Tuesday, a hospital spokeswoman said.
On Tuesday, would-be customers milled around outside yellow police tape strung across the parking lot at the FedEx store in Sunset Valley, watching investigators in FBI and police jackets circle the building.
Jessica Wilkinson said she was there to celebrate her 37th birthday with her mother and sister at a nearby restaurant. She didn't notice investigators at first, thinking the police tape had been strung because of repairs.
"We didn't know this was a crime scene," she said. "Should we stay here?"
Wilkinson was left concerned _ she's been receiving birthday gifts by mail, and expects more since her husband's birthday is Wednesday. She also worried about her sons, ages 8 and 4. Some of their classmates were evacuated from their homes following Sunday's explosion. But she said the attacks have been too random to justify varying her daily routine.
Wilkinson's mother, Kelly Metzler, 59, said she was reassured by the police presence and trusts the bomber's seeming brazenness will lead to an arrest.
"He seems to be a bit braver _ he's hitting facilities now with security cameras that might be able to catch him," she said. "This might be the last bomb _ hopefully."
Judy Faintich, 68, showed up at the FedEx store hoping to drop off a package, only to be stopped by the police tape. She had heard the news about the Schertz explosion, but not the potential connection to the store in her neighborhood.
She was soon joined by Megan Villaloboz, a local mother and pre-kindergarten teacher trying to pick up a package _ a replacement computer _ during her lunch break. When she saw the police, her face fell. This was her fourth time trying to make the pickup.
After the earlier bombings, Villaloboz, 30, said she became "hypervigilant." She told her children to stay in the car when they return home and spot packages on the stoop, waiting until she inspects the boxes. She has also tried to order less online, to limit deliveries.
"Now with it coming through FedEx, I doubt I'll order online," Villaloboz said.
She said she understood why investigators were waiting to release specifics about the devices until they catch a suspect. The influx of federal investigators also reassured her.
"They called in all those people, so I don't think they're doing a bad job. I just won't feel safe until they catch the guy," she said.
