Case file retention for private investigators

Every closed case leaves behind a file: notes, logs, reports, photos, hours of video, invoices, and personal information about people who never agreed to be in it. Keep it too briefly and you may not have it when a subpoena, a licensing inquiry or a malpractice claim arrives. Keep it forever and you carry an ever-growing pile of sensitive data that can leak, be stolen or be demanded.

The answer is a written retention policy: how long you keep each kind of record, why, and what happens at the end. This guide explains how to build one.

General information, not legal advice. Some states set record-keeping requirements for licensed investigators, and your clients may impose their own. Check your state’s rules (our state guides are a starting point) and have your attorney review your policy.

Why retention matters in both directions

Reasons to keep records:

• State licensing rules. Some states require licensed investigators to keep certain records for a set period and make them available to the regulator.
• Tax records. Invoices, receipts, mileage and payment records support your tax returns. The IRS publishes general guidance on how long to keep them, with longer periods in some situations; your accountant can tell you what applies.
• Claims and disputes. Fee disputes, complaints to your licensing board and professional-liability claims can arrive years after a case closes.
• Litigation. Your work may be relevant to a case that’s still running, or to one that hasn’t been filed yet.
• Client contracts. Insurers and corporate clients often specify retention terms in their vendor agreements.

Reasons not to keep records forever:

• Risk. Every old file is something that can be breached. The FTC’s guidance to businesses is to keep only what you need, and to dispose of what you don’t securely.
• Subpoenas. If you still have it, you may have to produce it.
• Cost and clutter. Storage isn’t free, and old files make current ones harder to find.
• Fairness to subjects. Files about people who were investigated, sometimes wrongly, shouldn’t live forever without reason.

Building a retention policy

1. List your record types

Separate them, because they need different periods:

• Engagement letters and contracts
• Intake notes, conflict checks and purpose screening
• Field notes and surveillance logs
• Reports delivered to clients
• Evidence: photos, video, audio, documents, captures
• Correspondence and messages with clients
• Time, expense and billing records
• Chain-of-custody records

2. Find the minimums

For each type, identify the longest period that applies from:

• Your state’s investigator record-keeping rules
• Tax record requirements
• Client contract terms
• Your professional-liability insurer’s recommendations
• The time limits for claims that could be brought against you (ask your attorney)

3. Set your periods

Pick a period for each record type that meets the minimums with a margin. Many investigators keep core records (contracts, reports, logs, billing) longer than bulky evidence, and return or hand over evidence to the client at the end of a case when the agreement allows. Whatever you choose, write it down and apply it consistently. A consistent, documented policy is much easier to defend than ad-hoc decisions.

4. Tell clients

Put your retention period and what happens at the end in your engagement letter: whether you’ll delete, return or offer materials to the client first. See PI retainer agreements: what to include.

5. Start the clock at the right time

Usually from case closure, or from final payment. Record the closure date in every case file so you know when the period ends.

Legal holds override the policy

A legal hold (or litigation hold) is an instruction to preserve information because litigation is pending or reasonably anticipated. When one applies, routine deletion stops for the affected material, whatever your retention schedule says.

Losing information that should have been preserved can lead a court to impose measures on the party that lost it, and can damage your client’s case. The Sedona Conference’s Commentary on Legal Holds is the standard reference on when the duty to preserve arises and how holds should work.

For a PI, holds usually come in one of three ways:

• The retaining attorney tells you. Record the instruction and what it covers.
• You receive a subpoena or preservation letter. Preserve the material, and contact the retaining attorney or your own attorney before responding.
• You learn of likely litigation involving a case you worked on. Ask the attorney whether a hold applies.

Practical rules:

• Mark held cases clearly in your system, with the reason and date.
• Stop any automatic deletion for those cases.
• Don’t reformat cards, wipe devices or discard notes that relate to a held case.
• Release a hold only when the attorney confirms in writing that it has ended, then return to your normal schedule.

If your case software deletes data automatically at the end of a retention period, make sure you can override that for individual cases.

Deleting securely

At the end of the retention period, if no hold applies:

1. Check again for holds and pending matters.
2. Notify or confirm with the client if your agreement says you will.
3. Delete everywhere: case software, local folders, external drives, email attachments, cloud storage, phone galleries, messaging apps and backups (or let backups age out on a known schedule).
4. Revoke any sharing links.
5. Sanitize or destroy retired media. NIST’s Guidelines for Media Sanitization (SP 800-88) describe how to clear, purge or destroy data on different kinds of storage. For a small practice, that usually means using the device’s built-in secure-erase or factory reset on encrypted devices, and physically destroying old drives and memory cards you won’t reuse.
6. Shred paper.
7. Record the disposal: what, when, how, by whom. Keep that record (it contains no case content) as evidence you followed your policy.

Encryption helps here. If your devices and storage were encrypted from the start, destroying the keys (for example, by securely resetting an encrypted device) makes the remaining data unreadable.

A starter checklist

• Record types listed
• Minimum periods identified (state rules, tax, contracts, insurance, claims)
• Retention periods written down
• Retention terms in your engagement letter
• Closure date recorded in every case
• Legal-hold process written down
• Secure deletion steps written down
• Calendar reminder to review expired cases every quarter

For the rest of your data-protection practice, see data security for private investigators and the evidence handling checklist.

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