A youth who threatened a police officer with a knife is being sought.
Derbyshire Constabulary today appealed for information after the shocking incident in Chesterfield.
The force said the officer had attempted to conduct a stop and search on the youth on Alexandra Road yesterday afternoon, at 2.55pm.
The youth, described as a white male aged between 16 and 18, reportedly threatened the officer with a knife before running off.
Firearms officers and the police helicopter joined the search for the youth, but he was not found.
Police said he has a slim build and was wearing a black waterproof jacket with the hood up and dark-coloured jogging bottoms. He had a black rucksack on his back.
Anyone with information is asked to call police on 101, quoting the reference number 18000134367.