Story highlights The suspected shooter was recently fired

He died from an apparent self-inflicted gunshot wound

The FBI in Birmingham had no immediate comment

A recently-fired employee opened fire at a UPS facility in Inglenook, Alabama, on Tuesday, killing two people before taking his own life, authorities said.

Responding to calls of an active shooter, officers with the Birmingham Police Department entered the building and found the three dead, including the gunman from what looked to be a self-inflicted gunshot wound.

Police said there were no other suspects. An investigation is under way.

"It will be a very methodical investigation, even though we have a pretty good idea about what transpired inside the business," Birmingham Police Chief A.C. Roper told reporters.

UPS released a statement confirming that two employees and a recently terminated employee are dead. They have not been identified, pending notification of next of kin.

"The safety of our employees is our primary focus, and UPS is cooperating fully with law enforcement," the company said. "Our focus now is on assisting the families of the victims, as well as the employees who work in this facility."

According to CNN affiliate WBRC , the two victims are believed to be higher-ranked employees. The gunman wore a UPS uniform.

"It appears that the shooter knew exactly who he wanted to target at the time," said Birmingham police Lt. Sean Edwards, WBRC reported.

The FBI in Birmingham had no immediate comment.

"Our thoughts and prayers are with the families and co-workers of those who died this morning," said Alabama Gov. Robert Bentley.

He added: "State law enforcement resources are available and ready to assist if needed as investigators work to determine a cause in this deadly shooting."