The Hindu : Cell phone technology comes in handy to investigators

Online edition of India's National Newspaper
Tuesday, Oct 08, 2002

Southern States

Southern States - Kerala

Cell phone technology comes in handy to investigators

By G. Anand

THIRUVANANTHAPURAM Oct. 7. Mobile telephone technology is fast becoming a powerful tool of investigation in the hands of State police investigators who are looking for leads and evidence in certain key cases, including the sensational `intelligence letter' forgery case.

It is reliably learnt that by verifying the Call Data Record (CDR) maintained by leading cell phone companies for marketing and billing purposes, police investigators can access stored data on cell phone location and calls made by subscribers.

Police can also reconstruct, down to the minute, the location of a cell phone user at any given time. Sources said that most cellular companies have their CDR archives going back to at least one year.

The standard radio-tracking technology used by cellular companies makes it possible for police to learn who a suspect met, where and even for how long the meeting was. Particularly so, if his or her contact is also a mobile user.

A mobile telephone is usually associated with one particular individual and provides his minute-by-minute location. Though different mobile phone companies use different methods for gathering and storing location and call information of their subscribers, basically, the technology detects the radio frequency sent from the mobile phone to service antennas or `towers' set-up by the company.

The sources said that a method called `triangulation' helps the company detect the caller's whereabouts within its multi-antenna area of operation. Surveillance of mobile phone locations is done by measuring the signal strength from the phone to nearby towers.

The company can get and store information about any cellular phone that is turned on and operating within the cellular network, whether or not the user is actually making a call. This is because cell-phones also transmit `handshaking' signals to nearby cell phone towers to let them know that the phone is `on' and within the range of the cell tower. ``Hence it is possible to find out even the itinerary of a travelling subscriber though he makes no calls, since the phone emits signals automatically when passing through areas covered by several towers. The coding information built into cell phones enables mobile companies to find out from which instrument the call was made irrespective of the SIM card used,'' a source said.

However, examining the voluminous CDR records and verifying the data from the base stations which pick up calls to reconstruct and pinpoint the whereabouts of phone users, is a painstaking task.

But through diligent work, police have successfully ensured conviction in certain `apparently clueless cases' by presenting cell-phone records as evidence, pointing to complicity of the accused in criminal cases. For instance, in the sensational `LTTE Kabeer' murder case in 1999, the police had used cell phone records as evidence during the trial.

Police sources pointed out that cell phones have become an effective tool in the hands of criminals for carrying out their operations in relative anonymity. ``Now we are turning the technology on them,'' an official said.

Keeping the security threats in mind, the Central Government had issued a directive to all cellular phone operators to issue pre-paid cards only after collecting proof of address and identification details of the user.

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