The clown was spotted riding with a group of illegal off-road bikers between Sheffield and Rotherham in Yorkshire.
One of the bikes is said to have been involved in a collision with a grey Fiat Punto in Ashpool Close, Woodhouse, just before 12.30pm on Saturday.
The rider then fled the scene, officers said.
The clown was among a group of illegal off-road bikers
Officers are appealing for information about the man dressed in a colourful one-piece suit and what appears to be a scary clown mask.
‘We’d now like to speak to the man in the costume, as we believe he can assist with our enquiries,’ officers added.
‘If you have any information that can help us, or dash-cam footage featuring this clown, please call 101.’