Police are investigating reports that a moped rider tailgated a car across uphill Lincoln before smashing the back window with a lump of concrete.
The moped rider was said to be wearing s distinctive “retro military style” helmet and had a full beard.
He allegedly began riding dangerously close to a white 14 reg Ford Fiesta near to the Carlton Centre on Outer Circle Road on December 5.
This was reported to continue throughout Outer Circle Road, before turning onto Greetwell Road and the Fiesta drove onto Monks Road.
Five minutes later, on Napier Street, the same moped reportedly drove up behind the Fiesta, and the rider threw a lump of concrete through the rear windscreen, smashing it completely.
The rider was described as a white male, in his 20s. The moped was described as silver/grey, and could have a partial VRM of “BK” at the beginning.
A Lincolnshire Police spokesperson added: “If you do have any information as to the identity of the rider, or you witnessed the incident in question, please call 101 and state that this is for the attention of PC 308 Pearson under Incident 274 of December 5.”