A former Gwinnett County police sergeant is accused of abusing his credibility as an officer to sell used cars, sometimes at high mark-ups.

Michael James Saunders, who resigned from the department last month after 18 years of service, was allegedly buying and selling used vehicles without a dealer's license, said Cpl. Illana Spellman, spokeswoman for the Gwinnett County Police Department.

Georgia allows a maximum of five vehicles to be sold privately each year without a license. A search warrant obtained Friday by The Atlanta Journal-Constitution showed that Saunders has sold at least 19 vehicles since 2006.

In nearly every case, Saunders represented himself as a police officer to the prospective buyer —- passing out his department business card or showing up to meetings with buyers dressed in uniform and a marked patrol car.

Saunders purchased abandoned or wrecked vehicles at auction from Lance Wrecker Service in Lawrenceville and Statewide Wrecker Service in Lilburn, according to the search warrant. In two instances, Saunders resold the cars for triple what he paid for them.

Saunders, 48, also is accused of forging the signatures of several Gwinnett County police officers on documents he filed with the state to verify ownership of the vehicles.

"Putting somebody else's name on an official piece of paperwork, that's a pretty clear-cut crime," said Gwinnett County District Attorney Danny Porter. "The officers whose names are on it said they didn't sign it."

Police said a resident complaint to the internal affairs unit prompted an investigation which lasted two months, culminating in Saunders' arrest Thursday at his apartment complex in Duluth.

Saunders is charged with one count of first-degree forgery, two counts of violation of oath of office, one count of racketeering, one count of false statement in application and three counts of illegally selling used vehicles.

He is being held on $103,900 bond at the Gwinnett jail.