BARRINGTON, Ill. (CBS) — Police in the northwest suburbs are warning people about someone who has been trying to impersonate them.

As WBBM Newsradio’s Bernie Tafoya reports, last week in Barrington, a man pretending to be a police officer allegedly pulled over a teenage girl who was driving on Northwest Highway.

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LISTEN: WBBM Newsradio’s Bernie Tafoya reports

The Daily Herald reports the man was driving an unmarked car, and used a flashing red light to force the 17-year-old girl to stop.

The girl pulled onto 20th Street near the Foundry Shopping Center. The man said he had stopped the girl for speeding, the newspaper reported.

The girl handed over her driver’s license, but the “officer” seemed to be more interested in personal questions such as where the girl worked and went to school, the Daily Herald reported.

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But there was a big tipoff that the man was not a real police officer. He turned off his headlights, which real police officers never do on traffic stops, the Daily Herald reported.

The girl refused to get out of her car when told to, and when asked if she could go, the man said yes, the newspaper reported.

The girl was not threatened or attacked, the newspaper reported.

The man was wearing a dark-colored shirt with a shiny badge over his chest, but there were no other police insignia, the newspaper reported.

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If you have doubt as to whether the person pulling you over is really a police officer, you are advised to call 911.