Cockapoo Benji was killed during a break-in at a property in Cobholm Close, Gorleston, near Great Yarmouth, on Wednesday afternoon.
The thieves stole a computer and other items from the home during the burglary between 3.50pm and 5.30pm.
It is believed Benji was drowned by burglars and his owner Mark Phillips returned home to find his pet in the bath.
He described the criminals’ actions as “barbaric” and said he was “in hysterics” when he discovered the killed puppy.
Norfolk Police has issued an appeal for information about the incident.
Detective Sergeant Richard Wallis said: "This is a particularly cruel crime and I would urge anyone who may have seen any suspicious behaviour in the area at around the time of the burglary to come forward."
Anyone with information should contact Great Yarmouth CID on 101 or Crimestoppers anonymously on 0800 555111.