A man assaulted an officer and then escaped from the back of a police vehicle in Lincoln.
Lincolnshire Police are now looking for a man who helped the offender escape from lawful custody.
The incident happened on the High Street at around 8:15pm on Sunday, August 12.
Police believe that the man pictured will be able to help with their enquiries.
Anyone with information about the incident is being urged to contact the force, quoting reference 402 of August 12.