Police in one of the nation's most impoverished cities are warning people whose cars turn up in video of drug hot spots.

Camden's police department and the Camden County Prosecutor's Office have sent 624 letters in the last four weeks telling owners their vehicles were seen in a high-crime area and that criminal or traffic charges may be filed if an investigation bears out.

Ninety percent of the letters were sent to suburbanites. Police Chief Scott Thomson tells The Philadelphia Inquirer it's good police work flagging people who would have been stopped by police in person if there were enough officers.

Some civil rights experts say the tactic is troubling and could get people in trouble just for being in the wrong place.  

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