How Long Must Evidence Be Retained?

How Long Evidence Must Be Kept: No Universal Answer

Evidence retention is not governed by a single mandatory period. The obligation to retain physical evidence—and the length of that obligation—depends on what the evidence is, what stage the case has reached, whether anyone has been charged, and what your state or the applicable federal law requires. The same principle that defeats a universal answer, however, creates clarity: the law binds retention to specific event markers. Retention continues until a triggering condition is met: the end of the statute of limitations, the completion of an appellate process, the expiration of a term of incarceration, or the passage of a retention period defined by statute. What starts the clock determines when it stops.

When no statute or case status marker applies, an agency's own evidence retention policy governs. When state law requires indefinite retention—as it often does for certain biological evidence in homicides—no expiration date exists at all.

Federal Criminal Cases: The DOJ Procedure

In the federal system, the Department of Justice Manual sets out the procedure for disposal of seized evidence in closed criminal cases. Under this procedure, evidence disposal may begin two years after the appellate court decision denying relief under 28 U.S.C. § 2255 for the last charged defendant, or two years after the 2255 limitation period itself expires [1].

Certain categories of evidence are exempt from this disposal process. Exempt evidence includes items seized in capital cases (those in which the punishment imposed was death), classified information, and biological evidence [1]. Federal law may also require retention of evidence for a designated period that has not yet expired; if so, the item must be retained until that period concludes. Historical preservation, law enforcement training, or law enforcement research value may also constitute grounds for an exception to the disposal process [1].

Who decides? The Special Agent in Charge (SAC) determines whether the reasons provided in support of a retention request are sufficient, and may grant or deny the request as to one or more items in a case while denying it as to others [1]. An appeal of a denial goes to the Deputy Attorney General [1].

Before any disposal, the evidence must be photographed, copied, recorded, or otherwise documented [1].

Biological Evidence: The Crime-Category Framework

Retention of biological evidence spans case status: an open investigation, charges filed, an adjudicated case (one in which final judgment has been rendered). The NIST Handbook on Biological Evidence Preservation provides guidance through this structure, with crime-specific retention obligations [2].

Whether an item actually contains biological evidence is a factual determination. An official with experience, training, and insight into the case context—such as a detective, crime scene technician, attorney, or laboratory staff member—should determine whether an item could contain biological evidence and should therefore be retained as such [2].

Open Investigation

For homicides, biological evidence collected in an open investigation should be retained indefinitely. For all other offenses, evidence should be retained at minimum for the length of the statute of limitations [2].

Charges Filed

Once charges are filed and court proceedings have begun or will begin, all evidence in the case should be maintained for laboratory analysis or court proceedings. Evidence custodians should be notified of case status to clarify retention obligations and guide disposition requests [2].

After Adjudication: Crime-Specific Retention

Once a case is adjudicated, the disposition of biological evidence follows crime-category rules. For homicides, sexual assault offenses, assaults, kidnappings or abductions, and robberies, biological evidence should be preserved through at minimum the period of incarceration, regardless of whether a plea was obtained [2]. For all other Group A and B offenses classified under the Uniform Crime Reporting program, biological evidence may be disposed of upon receipt of written authorizations [2].

If no charges are sought or a case is declined for prosecution, evidence need not be retained unless destruction is prohibited by statute [2].

Knowledge of your state's specific biological evidence retention statutes is essential, because retention obligations vary significantly by jurisdiction [2].

Digital Evidence: Organization-Defined Retention

Digital and multimedia evidence retention practices differ from biological evidence guidelines because no federal statute uniformly mandates retention periods. Instead, the approach is for each organization to define its own retention time frame—commonly five years or longer after case adjudication, extending through criminal and civil proceedings and the appeal process [4]. Some organizations adopt state statute periods; others conduct their own policy analysis.

Federal Court Recordings: A Permanent Category

Recordings of federal court proceedings in criminal cases involving the death penalty or capital habeas corpus must be retained permanently. All other federal court recordings in criminal cases are transferred to the National Archives 20 years after the case closes or when no longer needed by the court, whichever comes first [7].

Non-Evidentiary Video and State-Law Governance

Not all video from a crime scene is evidence. Body camera video or police department recordings that are not directly offered in a criminal case are governed by state law as to how long evidentiary material must be preserved, while retention of all other video is generally a matter of police department policy [8].

Who Authorizes Disposal

Retention, release, and disposal of evidence are restricted to Evidence and Property personnel and to personnel authorized by the agency executive leader [6]. In federal cases, the SAC has authority. In state and local cases, a designated investigator should provide written approval for disposal, or—if the assigned investigator is no longer employed—another designated investigator should give written authorization [6].

The Clock: What Starts It and What Restarts It

The retention clock begins at different points depending on what you are retaining:

• Open investigation (biological evidence, non-homicide): Statute of limitations for the offense
• Open investigation (homicide, biological evidence): Never expires—indefinite retention
• Charged case: Duration of prosecution through conviction and direct appeal
• Federal case, after conviction: Two years after final appellate ruling under 28 U.S.C. § 2255 or two years after the 2255 limitation period expires [1]
• Adjudicated case (homicide or violent felony, biological evidence): Through period of incarceration (varies by state statute)
• Adjudicated case (other offenses, biological evidence): As defined by state statute
• Digital evidence: Retention frame set by agency policy
• Declined prosecution: No mandatory retention unless statute prohibits destruction

The clock restarts if a case is reopened, if new evidence is discovered, or if appellate proceedings are initiated.

The Custody Record Outlives the Evidence

This is the point most retention schedules obscure: the chain-of-custody record is not evidence. It documents evidence. Because of that distinction, the custody record must be retained for a period of time even though the evidence it documents may be destroyed, lost, or returned [9].

The chain-of-custody record answers the question asked months or years after the evidence is gone: What happened to it? Who had it? When? For how long? Was it altered? Where is it now? Without the record, you cannot answer these questions. With the record, you can.

Specific retention periods for the custody record itself depend on the type of case and applicable local, state, and federal law. A general best practice is to retain custody records for the same period as the evidence, or longer—often indefinitely for serious crimes [9]. The record is inexpensive to store, often exists only on paper or in digital files, and is invaluable if the case is reopened, if an appeal is filed, or if questions about handling arise [9].

Who Determines What Is Biological Evidence

Not every item at a crime scene contains biological evidence, and not every item that could needs to be retained as biological evidence. An official with experience and training should make this determination—a detective, crime scene technician, prosecutor, or laboratory examiner [2]. The determination should be recorded in the case file and communicated to the evidence custodian so that proper retention obligations are applied from the start.

Illustrative Example: Three Scenes in One Case

Case No. 2026-CF-XXXX involves a robbery with aggravated assault. The investigation is open.

Month 1: Scene evidence collected A crime scene technician collects a swab from a wound, photographs, a discarded glove, and digital recordings from business cameras. The technician documents biological evidence (swab, glove interior) in the custody form. The case is open.

Retention clock: Statute of limitations for the offense applies. Example: in a state with a three-year limitations period for robbery, the biological evidence must be retained for at least three years from the date of the offense [2].

Retention clock: The digital recordings are retained per agency policy (example: until five years post-adjudication) [4].

Month 8: Charges filed A defendant is charged. Court proceedings begin. All evidence, including the biological items, must now be maintained for laboratory analysis and court proceedings [2].

Retention clock: Extends through conviction and direct appeal.

Year 3: Conviction and sentence The defendant is convicted and sentenced to 12 years incarceration. The case involves aggravated assault (a violent felony).

Retention clock: Biological evidence must now be retained through at least the period of incarceration [2]—in this case, at minimum 12 years from sentencing.

Year 15: Parole release The defendant is released on parole. The retention obligation for biological evidence does not automatically end. The specific end date depends on state statute governing assault convictions [2].

Retention of the chain-of-custody records, however, should extend indefinitely or per policy, because the record documents what happened to the evidence throughout the case, and that record may be needed if the conviction is challenged, if new evidence surfaces, or if the case is reopened [9].

Destruction Must Be Documented

When evidence is disposed of, the destruction should be documented—recorded in the custody record or in a separate disposal log. Photographs of certain categories of evidence (especially biological material) may be required before destruction [1]. This documentation becomes part of the permanent case record and answers the fundamental question: What became of this evidence, and when?

State Law Variation

No federal statute sets a universal evidence retention period for state and local law enforcement. Each state has its own code governing evidence retention, biological evidence preservation, and property disposition. Some state statutes are detailed and crime-specific; others delegate the matter largely to agency policy. Before setting retention periods or authorizing disposal, consult your state statute, your agency's evidence retention policy, and the prosecuting attorney for the jurisdiction [2].