On Thursday night, a woman was pulled over on Highway 102 near Lacewood Drive in Halifax after being followed by a black car with red and white emergency lights flashing.
When the woman stopped, the other vehicle pulled in behind her with its lights still flashing.
The driver and passenger became suspicious when they got a better look at the vehicle, and it did not resemble a police car.
The pair drove off and called 9-1-1, a move applauded by Halifax Regional Police.
Police described the vehicle as a black sedan with black tinted windows and red and white lights near the top of its windshield. The driver is only described as being in his 30s with a moustache.
Anyone with information or who may have video of the incident is asked to call police at 902-490-5020. Anonymous tips can be sent to Crime Stoppers by calling toll-free 1-800-222-TIPS (8477), submitting a secure web tip at www.crimestoppers.ns.caor using the P3 Tips app.
