114 voice on the tapes was not Khan's. It was a cover-up of an illegal wiretap. The conversations had been leaked out from the city crime branch. Four private detectives were arrested for illegally obtaining phone records of former Samajwadi Party leader Amar Singh in 2005. But what if an illegally monitored phone yields evidence of wrongdoing? Officials say a backdated application is sought from the home secretary. Every agency fills out an authorisation slip before placing a phone under surveillance. In the states, it is the state home secretary who signs this. Officially, telephones of politicians cannot be tapped-a qualifier on the slip says the surveilled person is not an elected representative. Before the advent of cellular phones, state agencies often strung out parallel lines from telephone poles, rented lodgings in the vicinity or even pitched a tent in the vicinity posing as nomadic tribes. Often the target would get to know due to the disturbance in the phone. Calls could only be listened to, not recorded. Cellphones gave organised crime syndicates mobility and anonymity as connections could be bought in fake names. In the mid-1990s, operators were ill-equipped to intercept calls. In the first instance of surveillance, the then deputy superintendent of the Uttar Pradesh Special Task Force (stf) Rajesh Pandey got a telecom engineer in Allahabad to devise a typewritersized interception box. The box was lugged around and connected to switching stations. Today, every cellular service provider has an aggregation station which is a clutch of servers called mediation servers (because they mediate between the cellular operators and the law enforcement agencies) to intercept phones. Two kinds of interception facilities are availableIntegrated Services Digital Network (ISDN) and the leased line. Under ISDN, a mediation server intercepts a call, and then transmits it through a Primary Rate Interface (PRI) line to the office of a government