"Chauhan said the stranger stopped him while he was on the way to his workplace and convinced him to sell his SIM card for Rs 500, saying his own had been blocked and that he needed another urgently. Chauhan agreed, but smelt a rat. As the stranger was walking away, he fished out a wireless key and disengaged a car lock. Chauhan jotted down the number of the car that blipped in response, on the same Rs 500 note. It was only when he showed us the note that we believed him," said an officer. The police obtained details of the car and arrested Lala. The SIM card was found in his possession.