What a Computer Forensic Investigation Actually Involves

Who This Is For

This article is useful for attorneys, business owners, HR departments, office managers, and organizations dealing with deleted files, disputed computer activity, employee departures, suspicious mailbox access, or litigation-related evidence.

1. Preservation Comes Before Review

A computer forensic investigation is not the same thing as opening a device and looking around. When a device, mailbox, cloud account, phone, or external drive may contain evidence, the way it is handled can affect whether the information remains useful.

What Preservation Usually Means

Depending on the case, preservation may involve a forensic image, documented file collection, mailbox export, Microsoft 365 log collection, phone preservation, external drive review, or documentation of device condition and identifying information.

Why Preservation Matters

Digital evidence is fragile. Files can change when opened, logs can expire, cloud data can be deleted, and normal usage can overwrite older artifacts.

Common Mistakes

Common mistakes include continuing to use the device, opening documents to see what is there, manually copying files without documentation, relying only on screenshots, or delaying until cloud records are no longer available.

2. The Investigation Should Start With Clear Questions

A forensic investigation should not be a random search through someone’s digital life. The examiner should understand the questions being asked before analysis begins.

Examples of Forensic Questions

Did someone copy company files? Was a USB drive connected? Were documents deleted? Was a mailbox accessed without authorization? Did an employee email files to a personal account?

Scope Matters

A narrow investigation may focus on one issue. A broader investigation may include a laptop, mailbox, Microsoft 365 records, OneDrive or SharePoint activity, browser artifacts, and remote access logs.

Facts and Interpretation Are Different

A report should distinguish between what the evidence shows and what the evidence may suggest. Opportunity is not the same thing as proof.

3. Common Evidence Sources

Computers and Laptops

A computer may contain evidence related to logons, recently opened files, deleted files, removable device connections, browser history, downloads, cloud sync folders, event logs, remote access tools, and user profile activity.

Email and Cloud Accounts

Email and cloud accounts may show messages, attachments, forwarding, inbox rules, sign-in activity, suspicious locations, deleted items, mailbox permissions, OneDrive or SharePoint access, Teams communications, and administrative changes.

External Drives and Removable Media

External drives, USB flash drives, SD cards, backup drives, and network storage can matter when reviewing file movement.

4. Deleted Files Are Only Part of the Story

Deleted File Review

Depending on the device and file system, it may be possible to identify or recover deleted documents, folders, file names, file paths, timestamps, partial file content, or temporary copies.

Artifact Review

Even when files cannot be recovered, artifacts may show that a file existed, was opened, was downloaded, was synced, or was located in a particular folder.

Timeline Reconstruction

The most useful findings often come from timing: when a file was created, modified, opened, deleted, downloaded, emailed, synced, or accessed relative to other activity.

5. Chain of Custody and Reporting

Documentation

Documentation may include who collected the evidence, where it came from, when it was preserved, what tools were used, what date ranges were reviewed, and what limitations existed.

Verification

Hash values, documented exports, tool logs, screenshots of tool output, notes, and preserved source data can help support the reliability of the review.

Clear Conclusions

A useful report explains what was reviewed, what was found, what cannot be determined, and what conclusions are actually supported by the evidence.