Police are appealing for information after a puppy was killed by another dog at the Land Rover Burghley Horse Trials on Saturday (September 6).
The incident happened at about 4pm as a 20-year-old woman was walking with her 10-week-old miniature long-haired dachshund on a lead.
The puppy was attacked by a dog described as a Staffy-cross, with a mottled effect brown coat. Its owner had it on a black lead and harness.
The woman found help but the puppy died from its injuries.
The man walked off with the dog without saying anything. He is described as white, in his mid to late 40s, slim, with greyish, receding cropped hair. He was wearing a light blue top and jeans.
Officers are treating the incident as an offence under the Dangerous Dogs Act.
Anyone with information should contact PC Norman McCallum on 101, or Crimestoppers, anonymously, on 0800 555111.