NORTHGLENN, Colo. -- Authorities continue their search for a man who posed as a police officer and pulled a woman over on Interstate 25 over the weekend.

The woman told authorities that the police impersonator had red and blue lights on the dash of his car.

The woman said when saw those lights flashing behind her, she pulled over on the side of the freeway. The man asked for her driver's license and registration and then had her perform a sobriety test, she said.

The woman told police the man then assaulted her and took off with her vehicle registration.

Police are looking for a white man in his mid-30s, with short, dark blonde hair, about 6 feet tall and 230 pounds. He was driving a dark-colored sedan and was wearing a navy blue button-up shirt with a shield-like badge and a belt with only a Leatherman-type tool attached to it, she said.

This incident occurred 12:15 a.m. Saturday in the 10300 block of northbound I-25.

If you have any information about the incident or if you think you can identify the man, contact Northglenn police at (303) 450-8853.

If you are being pulled over by an unmarked car with flashing lights, police say continue driving to a well-lit spot where you can crack your window to ask the officer to show his badge or call the police on your cell phone to verify if the officer is legitimate.

Impersonating a police officer is a felony, punishable up to $100,000 in fines and an eight-year prison sentence.