Some actions can extend the statute of limitations. In almost all states, fleeing the jurisdiction pauses the statute of limitations for the duration the suspect is not in the state. (Some states consider leaving the jurisdiction to be the same as fleeing, even if the intent was not to avoid criminal charges.)

Concealment is also generally grounds for tolling the statute.

And in some states, if criminal acts are related, the statute for the entire body of crimes doesn't begin until the last related criminal act.

See for a breakdown by state: https://criminal.findlaw.com/criminal-law-basics/time-limits...