Knowing how digital evidence is collected in forensic investigations is just as important as what data to collect. In this article, we’ll discuss the “hows and whys” of following a defensible process to maintain the credibility of your investigation.
First of all though, we’ll tackle the myriad of different types – and sources – of digital evidence out there. The key to ‘what to collect’ is to focus on the types of data that are most likely to be important to the case at hand and gather that information in a way that holds up in court. It’s also essential to have a clear strategy that ensures you capture everything relevant without overwhelming yourself with unnecessary data.
The eight types of digital evidence collected in forensic investigations
Knowing the different types of data, and what they can offer to an investigation, is essential in digital forensics because it helps investigators focus on the most relevant evidence. Each data type – whether it’s logs, metadata, or volatile memory – provides unique insights that can piece together a timeline, reveal user behaviour, or expose hidden activity.
Understanding what each data source brings to the table enables forensic teams to gather more precise information, build stronger cases, and ensure no crucial detail is overlooked. This targeted approach can not only save time but also strengthen the credibility of the investigation.
There are eight types of digital evidence that may be relevant to a forensic investigation. Let’s take a look at what they are, and what insights they have to offer.
Logs are records of activity on a system, capturing everything from login attempts to software errors. They help create a timeline of events and can show when suspicious activity started, or who accessed a system at certain times.
Multimedia files like video or photos can be a goldmine of evidence. This might be CCTV footage, images from mobile phones, or even screenshots. What’s important here is not just the content but also the metadata that tells you when, where, and how the file was created.
Email archives, chat logs, and backups of old data often contain information that’s no longer available elsewhere. These are especially useful for piecing together a timeline or uncovering communications relevant to the investigation.
This is the current, unaltered data stored on a device, including files, documents, and apps – basically everything that hasn’t been deleted yet. It’s often the first place to look when starting an investigation.

5. Metadata
Metadata gives you information about files themselves, such as when they were created, last accessed, or modified. It’s especially valuable for verifying timelines or understanding how a file was used or changed over time.
Residual or leftover data refers to fragments of files that have been deleted but can still be recovered. This is often key in uncovering attempts to hide or destroy evidence.
Volatile data exists in a system’s random access memory (RAM) and is lost when the device is powered off. Capturing this data in real time is crucial when you need to see what’s happening in the moment – such as active network connections or processes.
This refers to backups or copies of data that might be stored on other devices or in the cloud. Replicant data is often recoverable even if the original has been altered or deleted, making it an essential part of most investigations.
Why defensible processes matter when collecting digital evidence in forensic investigations
Once you know what data you’re after, when it comes to how digital evidence is collected in forensic investigations, it is imperative to preserve the data’s integrity. Here’s why following defensible processes is so important and how to do it right:
1. Maintaining evidence integrity
One of the biggest priorities is making sure evidence stays unaltered. This means creating exact copies of the data using specialised, write-blocking tools that prevent any modifications from happening during the collection process. By preserving the original in its untouched state, you ensure that the data remains credible.
2. Documenting the chain of custody
To prove that the evidence is authentic, you need to track its journey from the moment it’s collected until it’s presented in court. This is where a solid chain of custody comes in – documenting who handled the evidence, when, and why, so you can demonstrate it was managed responsibly.
3. Adhering to standardised protocols and methodologies
By sticking to industry-recognised frameworks and methodologies, you reduce the risk of mistakes and ensure your investigation is systematic and reliable. This also makes it easier to defend your findings if they’re challenged in court. Regular training and certification for investigators plays a significant role in upholding these standards.
4. Thorough documentation
It’s critical to document every step you take during the investigation, including the tools and software used, their versions and configurations, and all decisions made along the way. A good rule of thumb is that your audit trail should enable another investigator to precisely replicate your process and findings using the same tools and methodology.
5. Protecting data privacy and confidentiality
Investigations often involve handling sensitive personal or corporate information, so it’s vital to protect this data using encryption and access controls. Ensuring that only authorised individuals have access to the evidence safeguards against data breaches or misuse.
6. Staying up-to-date with evolving technologies
Digital forensics is constantly evolving, with new technologies, threats, and regulations emerging all the time. Investigators need to stay informed to ensure their practices remain current and effective, especially as legal requirements change.
Ensuring credibility and reliability in digital investigations
At Salient Discovery, we understand the importance of following best practices in every digital forensics investigation. Our team is committed to ensuring that all evidence is collected and handled in a way that’s both thorough and legally sound. Using industry-leading tools and frameworks, we help legal teams gather, analyse, and preserve digital evidence that holds up under scrutiny.
From recovering deleted data to investigating active systems, our experts use proven methodologies to give you a complete picture of the case. With the right combination of tools and expertise, we help you navigate the complexities of digital forensics, ensuring that no stone is left unturned.
An Introduction to Digital Forensics:
from defensible collection to analysis and insights
Read more in our Digital Forensics series to explore the complexities of collections, processing and analysis in more detail, and gain practical insights into how we can help uncover the truth in even the most challenging cases.
Introduction to digital forensics services – we share our thoughts on the applications and challenges.
Digital evidence collection – we discuss the two main techniques: Imaging vs. RAM Capture.
Preservation of digital evidence – we share our best practices about preserving digital forensic evidence.
Digital forensics meets eDiscovery – we show how to use eDiscovery tools to analyse digital evidence and uncover hidden patterns.