Police are hoping to track down a woman who tripped up a man running away from officers on Christmas Eve.
A group of men had allegedly threatened a member of door staff in Hertford Town centre.
Shortly after officers stopped a vehicle before one of the men inside made off.
But this quick-thinking member of the public stepped in to save the day.
Aaron Cadman (23) was then arrested and taken into custody.
Police are hoping to track down the woman, to personally thank her for her heroics.