MENOMONEE FALLS, Wis. (CBS 58) — A 65-year-old Menomonee Falls man has been charged with impersonating a police officer after prosecutors say he activated red and blue emergency lights to pass an off-duty deputy on Interstate 41.

According to a criminal complaint obtained by CBS 58, Steven S. Spatt faces one felony count of impersonating a peace officer. The charge carries a maximum penalty of 3 1/2 years in prison and a $10,000 fine.

The alleged incident happened shortly before 3:45 a.m. July 27, when Menomonee Falls police received a report of a vehicle with Florida license plates flashing red and blue lights on I-41.

The caller, an off-duty deputy, suspected the driver was impersonating a law enforcement officer.

Police located the unoccupied vehicle outside Planet Fitness. Officers entered the gym and learned from an employee that Spatt was in the locker room. They waited for him to come out before speaking with him.

According to the complaint, the off-duty deputy was driving south on I-41 when Spatt's vehicle approached at a high rate of speed, pulled in front of him and activated flashing red and blue lights while slowing down.

The deputy estimated Spatt's vehicle was traveling about 90 mph. He also reported seeing a spotlight, red LED lights mounted in the upper rear window and flashing red and blue lights near the third brake light.

Officers examining Spatt's vehicle reported finding multiple switches near the dashboard, a red LED light taped to the front dashboard, red lights in the upper rear window and a red-and-blue light bar near the third brake light. Police also found radio microphone equipment mounted near the ceiling.

Officers spoke with Spatt shortly after 4:15 a.m. Spatt confirmed the vehicle belonged to him and acknowledged it was equipped with red and blue lights, which he said he used while directing traffic at a flea market in Florida.

Spatt initially denied activating the lights and suggested the caller may have had something against him or law enforcement. Police then told him the caller was an off-duty officer.

After being arrested, Spatt agreed to speak with investigators at the police station. He acknowledged the emergency lights and siren were functional and said he had last used them while assisting with traffic control in Florida.

Spatt told police the off-duty deputy approached from behind at a high rate of speed and flashed his headlights. Spatt admitted he then activated the red and blue lights for several seconds to get the vehicle to back off and leave him alone.

Spatt is expected to make his initial court appearance Thursday.