How statutes of limitations work in criminal cases, and when the clock stops

A statute of limitations is a law that sets the maximum time after an offense within which prosecutors must file charges. Miss the deadline and the case is over, whatever the evidence shows: most federal crimes carry a five-year limitations period, homicide generally carries none, and state laws scatter across that spectrum. The rule exists not to protect the guilty but to protect everyone from prosecuting stale cases, when memories fade, evidence decays, and defense witnesses can no longer be found.

This article explains how the clock is set, when it starts, what stops and restarts it, and why some offenses keep getting longer deadlines. It publishes information, not legal advice; a limitations question in a real case requires counsel, because the calculation is fact-specific and sometimes dispositive.

The doctrine has been part of American law since the founding era, borrowed from English practice, and it applies to criminal prosecutions as well as civil suits. Its presence in a case is often invisible to readers — no one announces when the clock started — yet motions to dismiss on limitations grounds end prosecutions every year.

What are the actual deadlines?

Federal law sets the baseline at 18 U.S.C. § 3282: an offense not capital must be prosecuted within five years of its commission unless another statute provides otherwise. The exceptions carry the weight:

• No limit: murder, and federal capital offenses generally; terrorism offenses resulting in death.
• Eight years: many terrorism offenses; certain child exploitation offenses, some extended by later amendments.
• Twenty years: most federal sex offenses against children, and non-capital terrorism offenses, per amendments spanning 2003 to 2008.
• Ten years: most federal fraud against financial institutions; major art theft; certain immigration document offenses.
• Three years: certain tax and customs offenses under 26 U.S.C. and related statutes.

State law varies widely. Most states allow six years or less for common felonies, extend far longer for sex offenses against children, and remove limits entirely for homicide — though a few, such as Kentucky for some classes of offense, attach even homicide limits under specific conditions.

When does the clock start?

Ordinarily on the day the offense is completed. But modern statutes increasingly start it at discovery — when the offense is discovered or should have been discovered — because some crimes stay hidden for years. Federal fraud statutes and environmental offenses use this discovery rule, and it answers the common reader question of how a decades-old scheme can still be charged.

Some offenses start the clock only when harm appears. Civil statutes for latent injuries have criminal analogues where the harm manifests long after the act. The drafting choice matters more than the number: a 20-year period starting at discovery can reach back further than a 30-year period starting at commission, which is why defense lawyers read the start-date rule as closely as the length.

Related stories: How plea bargains work, and why most criminal cases end without a trial · How federal sentencing guidelines work after Booker made them advisory.

What stops the clock?

Tolling doctrines pause or extend the period in defined circumstances:

1. Defendant fugitive: the period does not run while the accused is absent from the jurisdiction, the rule in 18 U.S.C. § 3290 and most state codes. A person who flees returns to find the clock stopped for the years away.
2. Congressional extension: when a statute extends a limitations period, the extension applies to prosecutions not yet time-barred, including older cases, per 18 U.S.C. § 3283's savings clauses and court interpretations.
3. Charges already filed: once an indictment is returned, the prosecution generally relates back to that filing even if the indictment is later dismissed for technical defects and a new one is needed.
4. Defendant's absence from the state in some states: several jurisdictions toll when the accused lives elsewhere, even without flight.
5. DNA exceptions: a growing number of states authorize charging by indictment before DNA identification preserves the case; New York pioneered the John Doe DNA indictment practice in the 1990s, filing against an unidentified profile to keep sex-offense cases alive.

Victim age works differently: for child sex offenses, most states calculate the period from the victim turning 18, so a 10-year period may allow charging until the person is 28 or older.

Why do sex-offense deadlines keep changing?

Because of what the research on delayed disclosure showed. Studies cited by the National Institute of Justice and child-protection agencies found that child victims often disclose abuse years or decades after it occurs, and that DNA technology made decades-old cases provable. Legislatures responded in waves: federal amendments in 2003 and 2008 extended child sex-offense periods to 20 years or beyond, and state follow-ons multiplied through the 2010s.

A distinct strand is lookback-window legislation for civil suits, which temporarily suspends limitations for old claims; that mechanism is civil, not criminal, and is often confused in coverage with criminal charging deadlines. The criminal clock can be extended by statute or tolled in the ways above, but a prosecutor cannot revive an already-expired criminal case without new legislation — and even then, constitutional ex post facto limits bar reviving prosecutions that had fully expired when the extension passed, per the Supreme Court's line of cases beginning with United States v. Hall (1897).

What happens when the defense raises limitations?

The deadline is not enforced automatically; it is raised by motion. A defense motion to dismiss on limitations grounds triggers a factual inquiry — when the offense was completed, when the clock started, whether tolling applies — decided by the court. Unlike most dismissal grounds, limitations is not jurisdictional in federal practice: the indictment's filing date starts the analysis, and once timeliness is challenged, the government bears the burden of justifying tolling or extensions.

When the motion succeeds, the case ends on timeliness alone. The rule's defenders accept exactly that cost as the price of protecting everyone from memory-based prosecutions; its critics answer that modern forensics makes stale cases fairer than the doctrine assumes. Both positions have a decade of legislation behind them.

For readers, the practical takeaway is to check two dates in any older case: the date of the last act charged and the date the indictment was returned. If the gap exceeds the statute's period, the explanation will be one of the tolling doctrines above — flight, a discovery start, a John Doe indictment — and that explanation is itself part of the story.