PORTLAND — A U.S. District Court judge has denied a motion to suppress evidence in the case of an Auburn man charged with setting his ex-girlfriend’s apartment on fire.

Judge John H. Rich III issued his ruling Thursday against Trezjuan Thompson, 26, who was arrested Nov. 24, 2009, on a charge of arson. Thompson is accused of pouring gasoline in the apartment of Kristen Coolidge on Academy Street and setting it on fire, according to court records.

Thompson, who has 13 convictions since 2006, including six for violating conditions of release, was also charged with being a felon in possession of a firearm after police reported finding a handgun in the car in which he was riding, records state.

Auburn police determined Thompson had violated conditions of a protection order issued for Coolidge, his former girlfriend, and arrested him after the early-morning apartment fire and a report that he used a gun to threaten a man at the Big Apple store on Main Street that evening.

Thompson was arrested in Lewiston when police pulled over a rental car driven by Thompson’s girlfriend at the time, Lindsey Mercier. The judge’s decision indicated that police officers asked Mercier’s consent to have the car searched, and they subsequently found a 9 mm handgun beneath the spare tire in the trunk. Police also found a hole in one of the seats through which someone in the cabin of the car could place an object into the trunk.

According to the judge’s ruling, during “the morning of November 24, 2009, an e-mail was sent to the Auburn Police Department from the district attorney’s office indicating that [the department’s] request for an arrest warrant for the defendant … was going to be denied,” after the protection order issued for Coolidge against Thompson had been dismissed that morning.

In his motion to suppress evidence, particularly the handgun found in the trunk of the car, Thompson’s attorney argued that because the arresting officers “must” have had knowledge of the dismissal of this protective order, the defendant’s arrest lacked probable cause and was therefore invalid. The defense attorney also argued that Thompson’s Fourth Amendment right to privacy was violated by the police search of the car.

Justice Rich denied the motion, indicating that the arresting officers did have probable cause, particularly after receiving reports that Thompson used a firearm to threaten a man at the Big Apple store. He also said the arresting officers did not violate Thompson’s “legitimate expectations of privacy” by searching the car driven by Mercier.