A fired worker gunned down and killed two of his former colleagues during a shift change on Friday at a suburban Philadelphia book warehouse, The Associated Press reported.

According to Adam Rothberg, spokesman for Simon & Schuster, the killer had been fired for absenteeism. The two victims were working for the company's distribution center in Bristol, Pennsylvania. One of the victims was a veteran employee, while the other was a temp.

The fired employee went on a rampage at about 3:30 p.m. right during the shift change at the warehouse located about 20 miles north of Philadelphia.

Police investigators identified the killer as Robert Diamond, 32, of Bristol Borough, Bucks County District Attorney Michelle Henry confirmed. He collaborated with the police forces and turned himself in right at the crime scene.

He gave police personnel details about his crime. Diamond said that, after driving around for about an hour, he arrived at the facility and shot Angel Guadalupe, the temporary worker who was leaving the site. Diamond did not know Guadalupe, who was shot in his SUV. After the first victim fell from his vehicle, Diamond stood over him and kept firing, he told police.

Then the killer spotted forklift operator Reginald Woodson, 52, of Willingboro, N.J. The man was running towards a building to seek shelter in a building, but he was shot before he could take cover. Woodson was shot in the neck and back and died of his wounds.