Mobile Phone Analysis in Drugs Cases

Mobile phone analysis has become a pivotal tool in the investigation and prosecution of drug-related offences. With the rise of digital communication, mobile phones are often used to coordinate drug transactions, making them a treasure trove of evidence for law enforcement. Mobile phone analysis is the main area of digital forensic investigation for drugs related offences.  

For those facing such allegations, understanding how this evidence is used, and how it can be challenged, is crucial.  

At Olliers we have specialist expertise and experience in defending clients charged with serious drugs offences. Our experience dates back several decades and we have seen dramatic changes in the investigation landscape. Many of our lawyers are leaders in their field. Olliers is ranked as a top tier law firm by both the Legal 500 2025 and Chambers Guide 2025. We are a Times Best Law Firm 2025. We are the Manchester Legal Awards 2024 Crime Team of the Year retaining the title from 2023, an award we have won seven times since 2011. 

What Is Mobile Phone Analysis?  

Mobile phone analysis is an area of computer forensics. It involves the forensic examination of data stored on or transmitted through a mobile device.   

This includes:  

• Call history and voicemail 
• Messaging – both SMS (‘short message service’) and MMS (‘multimedia messaging service)  
• App usage and internet history  
• Wi-Fi history 
• GPS and location data  
• Deleted files and recovery attempts  
• Social media activity  
• Photographs and videos with metadata  

In drug cases, this data can be used to establish connections between suspects, track movements and uncover the extent of criminal networks.  

Deal Lines and Burner Phones  in Drug Investigations  

Alleged drug dealers are often accused of using multiple phones, known as “burners” to avoid detection. Burner phones cannot immediately be attributed to a particular user. These phones are used to communicate with buyers and suppliers. Analysis of call logs and text messages can reveal patterns of communication indicative of drug dealing. The onus is upon investigators to attribute a particular ‘burner’ phone to a suspect. 

Encrypted Messaging Apps  

Apps like WhatsApp, Signal, and Telegram are popular among drug dealers due to their encryption features. However, forensic tools can sometimes decrypt these messages, providing valuable evidence.  Our enchrochat blog discusses encryption in more detail. 

Location Tracking and cell site analysis 

GPS data, Wi-Fi connections and cell tower pings can help determine a phone’s location. Cell site analysis can establish the location of a device at the point of calls, downloads or messages being sent or received. This can be used to place suspects at drug transaction sites or link them to other members of a drug network. Crucially, investigators must be able to attribute the device to a particular suspect. Equally, cell site analysis can support an alibi.   

Social Media Activity  

Social media platforms can provide insights into a suspect’s lifestyle and associations. They can also assist in establishing an individual’s whereabouts on certain dates. Posts, messages, and even photos can be used to build a case.  

Search Warrants   

Under UK law police must obtain proper authorisation to access mobile phone data. This typically involves a warrant under the Police and Criminal Evidence Act 1984 (PACE). 

A ‘specific premises’ warrant allows officers to enter and search the premises which is specified on the warrant whereas an ‘all-premises’ warrant allows officers to enter and search all premises owned and controlled by a suspect. 

The ‘interests of justice’ test 

The police can enter a property if there is an argument that the delay that would occur in obtaining a search warrant would defeat the interests of justice. One example of this is if they believe that evidence is likely to be destroyed. 

Search of premises after an arrest 

S.32 PACE allows the police to enter and search any premises that the suspect was in at the time of their arrest or immediately before their arrest for evidence if the offence is indictable. 

The police must have reasonable grounds to believe they will find evidence connected to the alleged offence. Authorisation must be given by a senior police officer, meaning an inspector or above. 

S.18 PACE provides the powers for the police to search a premises whilst a suspect is still at the police station, if they have not searched the premises at the time of arrest. The police may enter and search any premises occupied or controlled by a person who is under arrest for an either way or indictable offence if they have reasonable grounds for suspecting that there is evidence on the premises that relates to the offence or to some other similar offence which is connected with or similar to that offence. 

We discuss police powers in more detail here.  

Data Integrity  

Defence teams should scrutinise whether the data was lawfully obtained.  

Any break in the chain of custody or improper handling of the device can lead to questions about the reliability of the evidence. And it is not just the device but the recovered data that requires a coherent chain of custody.  Defence solicitors should request full disclosure of forensic procedures used.  

Expert Interpretation  

Mobile phone data is complex and often requires expert interpretation. Misinterpretation of timestamps, location data, or app usage can lead to wrongful conclusions. At Olliers we often instruct independent digital forensic experts to review the prosecution’s findings.  

Challenging Location Accuracy in cases involving cell site analysis 

Cell tower data can be imprecise, especially in densely populated areas. Defence experts may argue that the phone could have been in a wider area than the prosecution claims. And, while cell site analysis is effective in placing a device in a general vicinity, it cannot pinpoint a particular property or even a particular street. 

This is where traditional forms of evidence come into play. This may be in the form of identification evidence and other witness testimony or forensic evidence, such as DNA, fingerprints banking evidence or CCTV, which can be used to back up conclusions or inferences drawn from cell site analysis. Frequently this evidence can be challenged. 

It’s important to understand that investigators will rarely be able to prove with absolute certainty who was using a certain phone at a particular time phone, it’s all about inferences – which can frequently be countered. 

Key points for the Defence to consider in all GPRS cases 

GPRS (General Packet Radio Service) is the protocol and standard for networks and it is used to transport data over the mobile networks. Essentially GPRS is the cornerstone in mobile communications and it bridges the gap between older and newer wireless technologies.  

It is important to note that GPRS can differ between different networks. It is different to calls and SMS from a timing perspective. The start time cannot always be relied upon as being correct. An expert should check the location provided by a GPRS record. Different networks handle data sessions differently. Analysts frequently get GPRS analysis wrong. Nothing should be accepted at face value. 

Alternative Explanations  

Just because a phone was at a location doesn’t mean the owner was. Phones can be lost, stolen, or used by others. Establishing this can cast doubt on the prosecution’s narrative.  

Highlighting Gaps or Omissions  

If the prosecution relies heavily on mobile data, any gaps, such as missing messages or unexplained activity can be used to question the completeness or reliability of the evidence.  

Olliers Recent Case 

In a recent Olliers case, our mobile phone expert was able to take the prosecution’s police phone analyst to task on the basis of his lack of actual expertise. In another case we used cell site analysis tracking our client to contradict the evidence of undercover officers, in other words the phone evidence supported the defendant’s alibi. We are often able to dispute potentially misleading prosecution attribution and co-location evidence. We have been able to demonstrate that a mobile phone which the prosecution sought to prove was related to our client by reason of cell site location was in fact cell siting in a different location 

Why Expert Legal Representation Matters  

At Olliers Solicitors we understand the critical role mobile phone evidence plays in modern criminal cases.  

Our team works with leading digital forensic experts to:  

• Review and challenge prosecution evidence  
• Identify procedural errors or breaches of privacy  
• Present alternative interpretations of data  
• Ensure your rights are protected at every stage  

Conclusion  

Mobile phone analysis can be a powerful tool in drug investigations but it is not infallible. With the right legal strategy and expert support, this evidence can be scrutinised, challenged and even turned to your advantage.  

If you or a loved one is facing a serious allegation involving mobile phone evidence, contact Olliers Solicitors today for expert legal advice and representation.