In the common law

Common law

Common law is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action...

 tradition, an acquittal formally certifies the accused is free from the charge of an offense, as far as the criminal law is concerned. This is so even where the prosecution is abandoned nolle prosequi

Nolle prosequi

Nolle prosequi is legal term of art and a Latin legal phrase meaning "to be unwilling to pursue", a phrase amounting to "please do not prosecute". It is a phrase used in many common law criminal prosecution contexts to describe a prosecutor's decision to voluntarily discontinue criminal charges...

. Under the rules of double jeopardy

Double jeopardy

Double jeopardy is a procedural defense that forbids a defendant from being tried again on the same, or similar charges following a legitimate acquittal or conviction...

 and autrefois acquit, an acquittal operates to bar the retrial of the accused for the same offense, even if new evidence

Evidence (law)

The law of evidence encompasses the rules and legal principles that govern the proof of facts in a legal proceeding. These rules determine what evidence can be considered by the trier of fact in reaching its decision and, sometimes, the weight that may be given to that evidence...

 surfaces that further implicates the accused.