A woman suffered serious injuries after police were called to reports of a fight in Whittlesey.
Officers were called at 8.26pm on Saturday, April 29, to the incident in Orchard Street.
A woman in her 20s was taken to Peterborough City Hospital by the East of England Ambulance Service with serious head injuries. A medical response car from Magpas also attended the scene to assist.
A 26-year-old man from Peterborough was arrested on suspicion of causing grievous bodily harm.
He has since been released under investigation.
Anyone with information about the incident should call police on 101.