Police were called at 11.35pm on Monday, July 23, to a flat in Cleatham in Bretton, Peterborough.
Four men armed with knives broke into the property but disturbed the homeowner as they attempted to steal his dog.
Speaking to the Peterborough Telegraph Laura Cuppello said her father-in law Anthony suffered "slashes" to his arm as he tried to stop the men taking his two-year-old female smooth coat Chihuahua named Tinkerbell.
The family are now appealing for any information that can bring their pet home.
A Cambridgeshire Police spokesman confirmed that they were investigating an aggravated burglary at the address but said they did not have descriptions of the men to release at this time.
Anyone with information about the theft should contact police on 101.