The sad incident occurred at around 7pm on Monday 30 November in Tothill Park, Lanhydrock Road, St Judes, Plymouth.
Police would like to speak to the owners of the offending dog.
The owner of the puppy described seeing a large dog running towards her and her puppy, knocking her off her feet before mauling her five-month-old pet to death.
Several members of the public reportedly assisted to stop the attack, to no avail.
The owner of the offending animal is said to have apologised and walked off.
The owner of the dog is described as being around 5’2” in height, in her 20s, with dark skin and dark hair. She was wearing a pink hooded top and jeans.
The offending dog is described as having the appearance of an American bulldog, with a large stocky body, brown or brindle and white in colour. It was wearing a collar with the word NERVOUS stitched into it. It may have been called Domino or Oreo. The dog is apparently walked in the park daily, more often by a male, and reportedly usually wears a muzzle and harness.
Police would like to hear from anyone who witnessed the incident, particularly the people who may have spoken to the owner of the offending dog.
Anyone who thinks they know the identity of the owner(s) is asked to contact police on 101 or via email at firstname.lastname@example.org quoting crime reference CR/100785/20.