SCHERTZ, Texas (CBSDFW.COM) – A package destined for an address in Austin exploded inside of a FedEx distribution facility outside of San Antonio early Tuesday. The package detonated just before 12:30 a.m. at the facility in Schertz, located about 20 miles northeast of San Antonio.

Sources stated that the package, which exploded was moving from an elevated conveyor belt down to a lower section when it exploded. The box contained shrapnel including nails and pieces of metal, sources added.

Officials told CBS 11 News Tuesday afternoon, that the second package was located in an Austin FedEx facility. They haven’t discussed the contents of that package, nor have they confirmed whether or not it contained explosives. But FedEx has confirmed the same person responsible for the package that blew up, shipped the second package, which was tracked down and turned over to law enforcement.

“The investigation is still underway,” stated Lt. Manny Casas with the Schertz Police Department, “but what we know is that the box was medium-sized.”

(credit: Jason Allen/CBSDFW.COM)

One woman who was working near the blast site was treated at the scene for a concussion and ringing in her ears, but none of the 75 employees at the FedEx facility were seriously injured. The facility has since been evacuated while authorities are at the scene.

FedEx released a statement on Tuesday morning that read, “We can confirm that a single package exploded while in a FedEx Ground sortation facility early this morning. One team member is being treated for minor injuries. We are working closely with law enforcement in their investigation.”

Federal officials confirmed late Tuesday morning that the package which exploded was mailed from a FedEx store in the south Austin enclave of Sunset Valley. Officials added that the intended target of the bomb was not the FedEx facility or anyone who lives in Schertz, but they would not say what mailing address the bomber put on the package.

Texas Attorney General Ken Paxton would only say that the package was mailed from Austin, and to an Austin home.

Officials with the Sunset Valley Police Department released a statement that said, in part, “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.”

Details about the other package bomb are scarce. During a press conference on Tuesday, Chief William McManus with the San Antonio Police Department said, “There was one other package that we believe was also loaded with an explosive device that they are working on right now.” The San Antonio Police Department is not handling the investigation.

The second box has since been removed from the Schertz distribution center.

The facility is now being investigated by several law enforcement agencies including the FBI, ATF and Homeland Security. An FBI agent told CBS News that “it’s more than possible” that this package is related to the four which have previously exploded in Austin this month.

“It would be silly for us not to admit that we suspect it’s related,” added FBI spokeswoman Michelle Lee.

The most recent explosion in Austin happened Sunday night and injured two people who were walking along a neighborhood road. Authorities believe that the blast was triggered by a tripwire. The first three attacks involved package bombs which were left on the doorsteps of homes.

Two people have been killed in the Austin explosions. The first incident, on March 2, left a 39-year-old man dead. The second explosion, on March 12, killed a 17-year-old man. The third explosion also occurred on March 12. Two additional people were injured in these first three explosions.

“We are clearly dealing with what we expect to be a serial bomber at this point, based on the similarities between what is now the fourth device,” said Chief Brian Manley with the Austin Police Department on Monday. He also urged residents, again, to not pick up or approach any suspicious packages.

The Austin Police Department said that, between 8 a.m. on Monday and 8 a.m. on Tuesday, officers responded to 420 suspicious package calls. This means that a total of more than 1,200 suspicious package calls have been investigated in the city since March 12.

Manley also made a public appeal Sunday, and again on Monday, for the bomber to call the authorities, while at the same time announcing that a reward of $115,000 is being offered for information that leads to the arrest of whoever is responsible for the explosions.

In regard to the bombing at the FedEx facility, Manley released a statement early Tuesday. “The Austin Police Department is aware of the incident that has occurred in Schertz,” he explained, “and is working closely on the investigation with our federal partners.”