Thames Valley Police is releasing an image of three boys officers wish to speak to about a sexual assault in Milton Keynes.
At around 5.30pm on 22 August this year, the two victims, both teenage girls, met three people in Xscape.
They exchanged Snapchat details and spent some time chatting before the group all left the centre.
They walked around Xscape on the Redway towards Fishermead where the three people sexually assaulted both victims by touching over their clothing.
The victims then ran away from the offenders.
It is believed the offenders travelled to and from Milton Keynes on the train and could live in the Leighton Buzzard area.
Investigating officer Detective Constable Lyndsay Gofton, based at Milton Keynes police station, said: “I am appealing for anyone who recognises the boys pictured in this image to please get in touch.
“If you are one of the boys pictured then please come forward as soon as possible as we believe you may have vital information about these sexual assaults.
“To contact us, call 101 or make a report on our website, quoting reference number 43220377235.
“Alternatively, you can provide information anonymously to independent charity Crimestoppers by calling 0800 555 111 or via its website.”