A package bomb blew up at a FedEx distribution center near San Antonio on Tuesday, hastening investigators to seek the public's help in determining if there is any link to four homemade bombs that have rocked the state capital of Austin this month.

Hundreds of federal investigators joined local authorities in probing the bombings, which the White House said do not appear to be linked to terrorism.
The latest blast knocked a female employee off her feet, police said. The package, filled with nails and metal shrapnel, exploded shortly after midnight local time (0500 GMT) at the FedEx Corp sorting facility in Schertz, Texas, about 65 miles (105 km) south of Austin, the San Antonio Fire Department said on Twitter.
Investigators were also examining a second suspicious package at the same facility, San Antonio Police Chief Bill McManus told reporters.
"There was one other package that we believe was also loaded with an explosive device that they are looking at right now," McManus told reporters in Schertz, about 20 miles (30 km) northeast of San Antonio.
In Sunset Valley, a town within Austin, police surrounded a FedEx store on suspicion it was linked to the Schertz bombing.
"The FBI is currently investigating a confirmed link between packages involved in the Austin bombing investigation and a mail delivery office in Sunset Valley. It appears that the source of the suspect packages was a private package delivery office in Sunset Valley," Sunset Valley police said in a statement.
Even with the apparent Austin link, it remained unknown whether the latest incident was the work of what Austin police said could be a serial bomber who is responsible for the four earlier devices that killed two people and injured four others.
The blast at the FedEx facility in Schertz was the fifth in the state in the last 18 days and the first involving a commercial parcel service.
"We are committed to bringing perpetrators of these heinous acts to justice. There is no apparent nexus to terrorism at this time," White House spokesman Sarah Sanders said in a Twitter post.
Investigators were trying to come up with a theory or intelligence regarding the motive for the bombings or identity of the bomber or bombers, a US security official and a law enforcement official told Reuters.
The FBI was investigating the FedEx package explosion as if there were a connection to the Austin bombings, the law enforcement official said. Both sources declined to be identified.
Federal authorities at the scene offered few details, telling reporters their probe was in the early stages and that the building would be secured before investigators could gather evidence.
Authorities offered a $115,000 reward to anyone providing information leading the arrest or conviction of the culprit, and public urged the bomber to communicate with them to explain the motivation for the attacks. We need the public's help right now," said James Smith, the assistant special agent in charge of the FBI's San Antonio office. 

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