A teenager was left with serious injuries after being attacked at Monkseaton Metro station.
The 16-year-old was assaulted at the Front Street entrance to Platform 1 on the evening of Sunday, January 20.
It is believed that those responsible later discussed the assault on another Metro route between 6.15pm and 6.30pm, travelling in the direction of West Monkseaton.
Police would like to talk to anyone who may have overheard the suspects and may be able to help with inquiries.
Officers would also like to trace a man who helped the victim following the assault.
The assault is believed to have taken place between 6pm and 6.15pm.
Anyone with information is asked to contact police on 101, quoting reference 008714S/19 or Crimestoppers anonymously on 0800 555111.