Fairfield police are warning residents about a scam phone call that looks like it's coming from the police department.

Lt. Jim Perez says his work number was recently used by a scammer pretending to be a police officer. The caller told a woman that police had a warrant for her arrest.

"The guy tells her he's a captain so-and-so with the Fairfield County police, which we don't have," says Perez. "We don't have county police in Connecticut. So that leads me to believe that the individual that's doing this is obviously from out of state."

The caller demanded that the victim give him gift cards to pay off her phony fine. But Perez says the victim didn't fall for it and she reported the scam to police.

Perez says he actually spoke with the scammer pretending to be him. The scammer called the victim while she was at the police station, making sure she didn't have an arrest warrant.

"It happens in city halls or town halls or any government agency, where these scammers are using those police numbers to try to build credibility," Perez says. "It's called 'source credibility,' which is one of the psychological tactics that they use."

Scammers often use "spoofing" apps to hide their real numbers, making an arrest nearly impossible in some cases.

Police advise anyone who thinks they might be a victim of the scam to get the caller's name and number, and to call their real police department.