After some "banging around in the bathroom," Facas said, Galiatsatos came out, then purchased a bag of chips - apparently to disguise his alleged intent - before leaving.
Facas went into the bathroom and noticed footprints on the toilet seat. He checked the drop ceiling and found a plastic bag that contained a paper bag.
"I got scared," Facas said. No, he didn't think it was a bomb. He did, however, worry that it might be dog poop "or drugs or money." He alerted the two officers, Eric Colella and Ryan Wiseley, who are lunch regulars.
The officers took the suspicious package outside and found three white mice in the paper bag, said Michael Chitwood, Upper Darby superintendent of police.
The officers saw Galiatsatos leaving Uncle Nick's Pizza across the street at 9000 West Chester Pike, where he allegedly had left six mice in a trash can, and arrested him.
"We have never had anything like this, where mice have been used as an instrument of crime," Chitwood said.
Officers have dubbed the case "The Great Pizza Wars" or "Mice vs. Pizza," Chitwood said.
"This is food terrorism by mice," he said.
After being taken into custody, Galiatsatos told detectives his pizzeria was struggling, Chitwood said.
"The defendant has had mice problems in his store," Chitwood said. "He felt the owners of Nick's and Verona put mice in his store, so he was getting even with them."
The mice, which Galiatsatos allegedly purchased Monday at a nearby pet store, were turned over to Upper Darby animal control, Chitwood said.
Galiatsatos will be charged with criminal mischief, disorderly conduct, cruelty to animals, and harassment, Chitwood said.
Someone answering the phone at Nina's Bella Pizzeria repeatedly hung up on a reporter Monday night.
Contact staff writer Mari A. Schaefer at 610-892-9149 or firstname.lastname@example.org.