Authorities in east Arkansas say a man has pulled off a string of robberies by posing as a police officer. One man is suspected of pulling the ruse on several occasions in Marion, West Memphis and Lonoke over the last week. In Marion, he allegedly knocked on motel room doors with a German shepherd by his side. He then told motel guests to show him their money for a police investigation, then ran off as soon as he had the money in hand. The real police are still looking for the suspect, a five-foot-eight, well-groomed black man who has been seen in at least two different vehicles. He is also wanted for robbing two roofers in Marion and a couple of truckers in West Memphis.