THIRUVANANTHAPURAM: With mobile phones emerging as an integral part of every person’s daily life, mobile forensics has become vital in crime investigation and even in prosecution. The state police have been equipped with state-of-the-art mobile forensic wings, a handful of trained officials and advanced tools for the purposes.
From identifying the accused through detailed analysis of call detail records (CDR) to tracking locations, mobile forensic played crucial roles in many crime investigations, the latest being the Jisha murder case in which about 25 lakh calls were analysed by the police. In the sensational T.P. Chandrasekharan murder case also, the police relied on CDR analysis to track the killer gang.
The probe into the conspiracy behind the TPC murder also reportedly led to some CPM leaders through CDR analysis. “In most crimes without an eyewitness, the investigations often start with examining the mobile phone of the victim. Since the call history of mobile phones are often limited, the CDR is taken from mobile service provider and analysed. It is in the next stage that the details of the calls that were connected through nearby mobile phone towers are analysed,” a police officer said.
CDRs provided by mobile service providers in soft copy format are analysed using software tools by giving different queries. Officials trained in CDR analysis do this as per the instructions of the investigation officers. Though this process police could figure out persons who were in the locality at the time of the crime as well as suspicious mobile phone calls made from the locality during the time of crime.
The tracking of the accused is done with the help of International Mobile Equipment Identity (IMEI) number, a unique number in each mobile phone handset. Once a mobile phone is in use, the IMEI number is registered on the system of the corresponding service provider. However, if a mobile is switched off, it will not be possible to track the phone with IMEI number, until the phone is switched on again.
The police also used to monitor the phone calls of close friends or relatives of the accused. CDR analysis reports are considered as valid evidence by the court and it is very effective to plug chances of accused claiming alibi. The mobile service providers are also bound to provide updated details of subscribers to the police regularly.
