A reward of £250 is on offer for information leading to the return of a dog.
Five-year-old Rocco has been missing since Friday, September 21.
He was last seen near Catcote Road in Hartlepool.
Rocco is a long-haired fawn and white Chihuahua who is microchipped but has no collar.
He is described as friendly.
Those appealing for information say that he has since been seen around the Brierton area in Eskdale Road.
Anyone with information regarding the dog's whereabouts are asked to call 07543769356.