AUSTIN/SAN ANTONIO, Texas- A homemade bomb blew up at a FedEx Corp FDX.N distribution center near San Antonio early on Tuesday, officials said, and the FBI was investigating whether it was linked to a series of four homemade bombs that struck capital city Austin this month.
Officials did not say if they believed the device, which exploded at the FedEx facility in Schertz, Texas, was the work of a "serial bomber" who police feared may be responsible for the four earlier devices, which killed two people and injured six others. One person received a minor injury, officials said.
The first three were parcel bombs left on residential doorsteps, while the fourth on Sunday was apparently set off by a trip wire. Police warned that the latest bomb had a more sophisticated design than the others.
The package exploded shortly after midnight local time (0500 GMT) at the facility, about 65 miles (105 km) south of Austin, the San Antonio Fire Department said on Twitter.
Agents from the Federal Bureau of Investigation and the Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene and investigating, fire officials said. They did not give the address for the package, which was filled with nails and metal shrapnel.
"We are investigating it as being possibly related to our open investigation," FBI spokeswoman Michelle Lee told the Austin American-Statesman newspaper. "We can't know for sure until we have an opportunity to look at the evidence itself."
One person was treated at the scene for a non-life-threatening percussion-type injury, officials said. Local media said the employee reported ringing in her ears.
About 75 people were working at the facility at the time, fire officials said.
Police did not immediately say if the explosion appeared to be linked to the four others. The first three were parcel bombs dropped off in front of homes on Austin's east side, with the fourth an apparent trip wire device that went off on the city's west side on Sunday.
The four devices were similar in construction, suggesting they were the work of the same bomb maker, officials said.
FedEx officials could not be reached for immediate comment.
The first two bombs killed black men and investigators believed that the third, which injured a Latina woman, may have been intended for a black family's home, police said, raising the possibility they were a hate crime.
Sunday's trip wire bomb, which injured two white men, went off shortly after police made a rare public call to the suspect to explain his motives.
Austin, with a population of nearly 1 million people, is home to the University of Texas and a plethora of technology companies and has been one of the fastest growing major U.S. cities.
(Additional reporting by Brendan O'Brien in Milwaukee Writing by Scott Malone Editing by Matthew Mpoke Bigg and Jeffrey Benkoe) ((firstname.lastname@example.org; 414 937-5300;))