He was suspended with pay pending the outcome of the investigation, said Mesquite police spokesman Lt. Bill Hedgpeth, who declined further comment.
NBCDFW.com called McCallister’s home for comment. A woman who answered the phone, who did not identify herself, said, "Come on, guy. I mean, do you really think we're going to talk to you guys?"
She would not offer any further comment.
On Tuesday, the FBI placed $100,000 in marked bills in a car driven by an undercover agent, the complaint said. McAllister was then lured to assist in what he believed was a drug arrest.
Secret cameras installed in the vehicle captured McAllister stuffing a bundle of $2,000 into his pants, the complaint said.
Agents later followed him to Town East Mall, where he bought a $480 watch at a store called The Buckle. The FBI said it recovered the money from the store and it matched the bills from the sting operation.
The FBI began its investigation after receiving a tip in December that McAllister was stealing cash during drug busts, the court documents said.
McAllister was charged with theft of government money. If convicted, he faces up to 10 years in prison and a $250,000 fine. (Read the entire complaint from United States Attorney James Jacks here.)