MUMBAI, July 9 -- Impersonating a police officer to cheat unsuspecting victims is one of the oldest tricks in a fraudster's book - but pulling it off right under the police commissioner's nose? After a fairly successful run as a conman, a 51-year-old man has been arrested for cheating several shopkeepers right outside the Mumbai police headquarters, by posing as an IPS officer. "We arrested Sandeep Narayan Gosavi, alias Sandeep Karnik, alias Dinesh Bodulal Dikshit, on Monday. We laid a trap for him at the Aarey Stall outside the Mumbai Police Commissioner's office, and picked him up from there after the complainant pointed him out to us," said a police officer with the Mumbai crime branch. Gosavi's run came to an end on July 7, after he attempted to dupe Nazim Kutchi, 24, who runs Saqibi Collections, a stall that sells mobile phone covers at Crawford Market. Introducing himself as 'Sandeep Karnik', Gosavi told Kutchi he knew a common friend who visits his shop. When Gosavi claimed to be a senior police officer in Maharashtra, Kutchi fell for the lie, as he had seen Gosavi chatting with uniformed policemen, who also visited his shop. On July 5, Gosavi told Kutchi he had left his phone in his car and he needed one urgently. He took Kutchi's mobile phone, claiming his driver would return it in a couple of days. Kutchi wasn't worried. After all, the man was a cop, right? When Gosavi failed to show up, he told Kutchi over the phone that his driver was delayed and he would pay for the mobile. When even that did not happen, Kutchi made some inquiries with other shopkeepers outside the police commissioner office, and learnt that Gosavi had conned many of them too. Each time, he had posed as "senior police officer, Sandeep Karnik". Kutchi then lodged a complaint with the police. "We have arrested him and are questioning him," said a senior police officer. He confirmed that Gosavi had cheated several people posing as 'Karnik'. Considering that the Nashik police commissioner is 'Sandeep Karnik', HT spoke to him. He said he had no idea someone was impersonating him....