A woman was injured after being struck by an object thrown from a passing car in Chesterfield.
The 74-year-old was walking along Lockoford Lane, near to the Donkey Derby pub, when she was hit.
Derbyshire Police said she was struck in the face by an object and knocked to the ground.
The pensioner, who suffered bruising to her eyes and face in the incident, told police officers she heard two cars speeding off afterwards.
A Derbyshire Police spokesman said: "Police are appealing for witnesses after a pedestrian was struck in the face by an object from a passing car in Chesterfield.
"A 74-year-old woman was walking along Lockoford Lane, near to the Donkey Derby pub, towards the Tesco store, when an item was thrown out of a car, which hit her in the face and knocked her over.
"She heard what she believes to be two vehicles speeding off, but it is possible one may have been another motorist who saw the incident and followed the other vehicle.
"Officers would like to track down the vehicles and their occupants and are appealing for anyone who may have seen the incident to contact them."
Anyone with information about the incident, which happened between 7.30am and 8am on Wednesday, August 10, should call PC Simon Richardson at Derbyshire Police on 101.