Police are appealing for information after a 15 year-old boy was assaulted inside Toys R Us at Teesside Park.
The attack is said to have happened on Saturday, December 5, at 5:30pm.
The victim was taken to James Cook University Hospital, in Middlesbrough, where he was treated for facial injuries and was later released.
A 26-year-old man has been arrested on suspicion of assault and has been released on bail pending further enquiries.
Police are appealing for anyone with information or anyone who may have witnessed the incident to contact DC Andrew Letts on the non-emergency 101 number, Crimestoppers anonymously on 0800 555 111 or www.crimestoppers-uk.org.