A puppy which had to put down after being severely injured was not attacked by youths as originally thought, police have confirmed.
Officers have been investigating the possibility the dog's injuries were caused at the home of a man who took it to a rescue shelter.
A 31-year-old man was arrested on suspicion of cruelty to an animal, but was later released without charge.
A Northumbria Police spokesman said a file would be passed to the RSPCA.
A man said he rescued the puppy when he saw it being thrown about by a gang of youths near Temple Park leisure centre in South Shields.
He took the six to eight-week-old Labrador cross to St Francis Animal Rescue, in South Shields.
The puppy, which was called Maddy by workers, was put on a drip, but vets later decided to put it down because of the extent of its injuries.
A spokeswoman for the RSPCA said: "Should the police pass the file to us, we will be more than happy to help in bringing the person responsible to justice."
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