Police are hunting for a man caught on camera seen swinging a small dog around his head using the animal's lead.
The video was recorded in Stevenage in Hertfordshire last night. It shows four men walking along a pavement with the Chihauhau.
One of the men then suddenly lifts the dog up by its lead and repeatedly swings the animal around his head.
Hertfordshire Police say the pet's owner had allowed her dog to be taken for a walk but was completely unaware of what happened until the video appeared on Facebook.
Watch the video in full below - please note it contains footage you may find distressing
The dog was not injured and has been returned to its owner.
If you have any information you can contact police on 101 quoting crime reference number E1/14/4685. Alternatively call Crimestoppers anonymously on 0800 555 111. A reward is on offer.