MUMBAI - Cinematic icon Amitabh Bachchan approached the police to solve the mystery over "dirty abusive sms" that he had been receiving for a year, on Monday, when his Twitter account was hacked. The 72-year-old made a complaint via a letter addressed to a senior police inspector of the Juhu police station here. In the letter, a scanned copy of which is with IANS, he wrote: “Dear Sir, Through a certain period of time,