An investigation has been launched by the RSPCA after a Staffie was found with a one-inch, infected stab wound.
The brindle and white dog was spotted by staff at Gateshead Metro station after he wandered off a train alone with a wound to his back.
Staff contacted the RSPCA at around midday on Saturday (January 12), and the charity is appealing to the public for more information about the dog, and his condition.
Rowena Proctor, RSPCA inspector, said: "The poor boy was crying out, whimpering and clearly in some distress. He had a one-inch wound to his back, which was infected."
“I took him straight to the vets who say that the injury definitely appears to have been caused by a sharp object.
“At this point, we don't know if this has been an accident or if someone has done this on purpose to him.
“Despite efforts to track down where he has come from on CCTV, we are no further forward yet, and hope that someone out there will know something about him."
Inspector Proctor said the dog is around eight years old, unneutered and microchipped - but not registered.
Because of this, there is no way to trace the owner.
The inspector added: “He appears to be in good condition so there may be someone looking for him.”
The dog is under vet treatment in RSPCA care while the investigation continues.
Anyone with any information should call the RSPCA inspector appeal line on 0300 123 8018 and ask to leave a message for Inspector Proctor.