The incident is believed to have happened outside Sainsbury’s, in Nottingham Road, between 4pm and 5pm on Monday January 31.
Officers say the teenage victim was thrown to the ground after being hit.
A 60-year-old man, from Melton, was arrested, on February 25, on suspicion of common assault and he has since been released on bail.
In an appeal to the public, Pc Rebecca Angel, the investigating officer, said: “Please cast your mind back.
“Were you in the car park when this incident occurred? What did you see? What do you remember?
“I’m particularly keen to speak to anyone who has a dashcam in their vehicle.
“Any information or footage you have, no matter how insignificant you think it is, could help.”
Information can be given online at https://www.leics.police.uk/ro/report/ocr/af/how-to-report-a-crime/ quoting reference 22*61004 or by calling police on 101.