Mumbai: Andheri police arrested a civil engineer for allegedly trying to extort Rs 10,000 from a milk vendor by threatening to book him and his son in a case for illegally selling tobacco (gutka) at their shop. Police also launched a search for his accomplice. The duo allegedly used a police identity card (ID) to extort money from Shivsing Balla (48), the dairy operator from Chakala, on Aug 2.Police suspect that the accused took up the crime to earn fast money. The accused used real serving police’ identity cards. Their plan failed when the shop owner noticed that the photo on the police ID card that they flashed did not match with any one of the two who claimed themselves as police.The accused, identified as Deepaksingh Thakur (33), arrived with his friend Gulabsing Thakur in an SUV from Mira Road and stopped outside the complainant’s shop in Chakala, where the complainant’s son was managing the shop, police said. Deepaksingh was in police custody, while the police team searched for Gulabsing on charges of cheating and impersonation.