EDITOR'S NOTE: This story has been updated to include the DA's prosecution decision.
A 24-year-old McFarland man was knocked out and injured during a fight in downtown Madison early Saturday morning, according to a release from Madison police.
Witnesses told police two men were fighting each other in the 300 block of North Frances Street when a third man punched the victim from behind sending him to the ground.
A security guard was able to give police details that led to apprehensions.
The two men who were fighting were cited for disorderly conduct. Police said the man who delivered the punch from behind was arrested on suspicion of substantial battery. The district attorney's office has declined to prosecute the case.
The victim suffered broken teeth and multiple stitches.