Modern criminal investigations hinge on an invisible yet crucial element: digital evidence. Over 95% of criminal cases now depend on some form of electronic data. Digital footprints from smartphones, laptops, security cameras and social media platforms play a vital role in solving crimes.  

The digital forensics process has transformed how investigators crack complex cases by uncovering key evidence, building timelines and linking suspects to crimes. And most importantly, validating all of this data.  For example, my analysis and testimony in the high profile Karen Read Murder Trial demonstrates the importance of validation. In Part 1 of a two part series, I chat with my colleague Heather Barnhart about a timestamp which created a swarm of misinformation and controversy.

A case’s success in court often depends on how investigative teams handle and analyze various types of digital evidence. Law enforcement agencies worldwide use digital forensics to methodically collect, preserve and examine electronic data. Understanding the digital forensics life cycle and following best practices are essential for ensuring the integrity and admissibility of evidence.  

Digital Forensics Best Practices  

When collecting digital evidence, investigative teams must adhere to a set of best practices to ensure the integrity and admissibility of the evidence.   

  1. Scene Preservation: Secure any digital evidence including placing the device in a faraday bag, which blocks signals and prevents unauthorized access to potential digital evidence sources.  
  1. Comprehensive Documentation: Photograph and document the state of all digital devices, their locations, and any visible information on screens. Proper evidence documentation is crucial for maintaining the chain of custody for evidence.  
  1. Power Management: Maintain power to active devices and avoid turning on devices that are powered down. This is especially important for preserving volatile data. 
  1. Network Isolation: Enable airplane mode on mobile devices to prevent remote access or data alteration, which is critical for maintaining data integrity.  
  1. Write Protection: Employ hardware write blockers when accessing storage devices to prevent inadvertent modifications and ensure the evidence remains forensically sound.  
  1. Forensic Imaging: Create bit-by-bit copies of storage devices rather than working on original evidence. This file copying for preservation technique is essential for maintaining the integrity of the original data.  
  1. Chain of Custody: Meticulously document every transfer and action taken with the evidence. This chain of custody for evidence is crucial for proving the authenticity of digital evidence in court.  
  1. Environmental Considerations: Use anti-static bags for digital evidence storage and protect devices from extreme temperatures or magnetic fields to ensure media longevity. 
  1. Dynamic Data: Collect data from mobile devices as soon as possible, as phones update over time based on location, activity and other usage information. 
  1. Legal Authorization: Based on your jurisdiction, ensure all necessary warrants or written consent are obtained before accessing or seizing devices, establishing proper legal authority for the investigation.  

Challenges in Digital Evidence Analysis  

While these best practices lay the groundwork for solid evidence collection in digital forensics, the field is always changing. As technology grows more complex, so do the challenges faced by investigative teams.   

Examiners and investigators face several significant challenges in modern digital forensics investigation processes:  

  1. Data Volume: The increasing storage capacity of devices presents vast amounts of data to analyze, making it challenging to identify relevant information efficiently.  
  1. Information Sharing: The need to share large volumes of data securely among team members and relevant parties presents logistical and security challenges in evidence management. 
  1. Cross-Device Analysis: The ability to review multiple digital devices simultaneously can reveal critical connections that might otherwise be overlooked. For instance: 
  • Correlating a suspect’s location data with the activation of specific apps or features 
  • Corroborating locations with other suspects or victims 
  • Identifying patterns of communication or proximity between individuals who claim no association 
  • Tracing the spread of illicit drugs through seemingly unconnected individuals 
  1. Legal Constraints: Balancing comprehensive searches with privacy rights requires carefully crafted warrants and strict adherence to legal guidelines.  
     

Conclusion  

Digital evidence is now a crucial part of nearly every investigation, changing how cases are handled and solved. Instead of focusing on individual devices, investigative teams are now looking at evidence from a broader perspective. As technology advances, so do the methods for collecting and analyzing digital evidence, with digital forensics constantly adapting to new challenges.  

The ability to examine data across multiple devices at once is a major step forward, revealing connections that might otherwise get missed. For law enforcement and legal professionals, keeping up with these technological changes is essential. Proper handling of digital evidence and an auditable chain-of-custody can make or break a case, highlighting the need for continuous training and investment in digital forensics.  

In our connected world, the importance of digital evidence will only increase. Those skilled in its collection, analysis and presentation will be best positioned to ensure justice. As computing devices become more complex in crimes, digital forensics must keep evolving, adopting new techniques and software to tackle future challenges.  

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