Suffolk police are investigating a Portsmouth firefighter who performed a traffic stop on a car in Suffolk.

The incident happened Jan. 24 about 4:30 p.m. in the 300 block of Pinner Street, city spokeswoman Debbie George said.

George said the man, who works for the Portsmouth fire marshal’s office, observed a vehicle swerve into oncoming traffic, almost striking two vehicles.

The man was operating his unmarked work vehicle issued by the city of Portsmouth. He activated the blue police lights installed on his vehicle to conduct a traffic stop on the car.

At that time, two Suffolk police officers drove by the traffic stop, George said. They noticed it was someone they did not recognize driving an unmarked car and not carrying a firearm, so they stopped.

The investigation still is ongoing, and no charges have been filed yet, George said. Police are conferring with the Commonwealth’s Attorney’s office to determine potential charges, she said.

George said fire marshals do have limited powers of arrest in Virginia, but it is so far unclear whether the man was within his authority when he conducted the traffic stop.