CYFOR Blog

Instructing Cell Site Analysis Experts in legally aided matters is crucial if admissible digital evidence is to be ascertained for presentation in court.

What is cell site analysis?

Cell site analysis is a forensic technique that examines the usage of a mobile phone when it makes or receives calls, sends or receives an SMS message, or connects to the internet. These records are maintained by the relevant network and cannot be deleted. This analysis can be used to  identify the area a mobile phone was located by examining the cells used at the time. Expert opinion can be given on where those cells serve, or a Radio Frequency (RF) survey can be completed to establish where those cells serve. This information can prove invaluable during the course of an investigation or during a court case.

As many modern mobile phones are set to automatically retrieve emails or social media data, this means that there could be more data than simply calls and SMS messages to assist in locating a phone. Investigating officers will use cell site analysis to determine whether a suspect was at a particular location at a specific time. Cell site evidence is unlikely to be able to pinpoint a phone to an exact location, so we encourage our defence clients to instruct us to test this evidence for reliability and establish other potential areas of coverage of the cell(s) in question. Conversely, the defence may retrieve this information in order to be able to prove that their client, or their mobile phone, was at an alternative location at a particular time.

CYFOR’s mobile forensics have had considerable success in cross referencing location data from within a phone to pinpoint a device proving that the defendant’s phone was actually elsewhere at the time of the offence. This then casts doubts on the assertions of the prosecution that the phone had to be at the location of the offence.

Cell Site Analysis Investigation

For example, in a recent CYFOR investigation, the defendant used his phone at the time of a robbery at a betting shop, and the prosecution produced maps showing his phone in use at the location. His defence was that he was at the gym, which was located 1.5 miles from the betting shop. When CYFOR repeated the cell site surveys, the area covered by the cell attributed to the betting shop, also covered the gym. This invaluably aided his defence case and led to a successful outcome.

Instructing cell site analysis experts should always be considered an imperative strategy, as the prosecution’s interpretation of the cell site analysis evidence should not be relied upon.