A man suspected of posing as an FBI agent was arrested in El Monte on a charge of attempted robbery after telling a store manager that he was checking for counterfeit bills. William Francis Wilson, 43, of Canyon Country was booked for investigation of the attempted robbery of the Carlton Market and was being held in lieu of $125,000 bail, said El Monte Police Lt. Ken Jeske. He is also being sought by federal authorities in another case. Wilson was arrested near the market after an employee called police to describe what they believed was a robbery attempt, Jeske said. Police have been looking for a man who goes to businesses and says he is an FBI agent searching for counterfeit bills, Jeske said. The man looks at the money, then holds up the business.