A statute of limitations was a type of law.
Such a law placed a time limit on the prosecution of a crime or class of crimes, ensuring that governments did not endlessly pursue suspected criminals without charging them. After the time limit had passed, no charges could be filed.
On the planet Lissepia, bank robbery carried a statute of limitations of nine Earth years. That statute was the reason the conspirators of the Lissepian Mother's Day Heist Larell, Hain, Nahsk, and Krit did not attempt to recover the proceeds of the heist from fellow conspirator Morn, who had hidden them, until after the statute of limitations had expired. (DS9: "Who Mourns for Morn?")