The RSPCA is trying to track down who is responsible for partially severing a dog's head and then dumping the body on her owner's patio.
Hollie, a Staffordshire bull terrier, was taken from her owner's garden and killed elsewhere, RSPCA investigators believe.
West Midlands Police is conducting a joint inquiry with the animal charity into the gruesome discovery on 19 May.
The dog was found by her owner Andrea Jarvis when she returned home from work in Bilston, Wolverhampton.
She found Hollie after trying to call her in for her dinner. The dog's leg had also been severed.
Ms Jarvis, a carer who lives with her 18-year-old son, Jack, said finding Hollie's body was "horrific and upsetting".
She said: "I just couldn't believe what I was seeing - Hollie was dead and her body had been left cut up in such a terrible way.
"We have had Hollie for 13 years and she was such a loving dog I can't believe this has happened.
"When I couldn't find her I expected she was curled up on my bed - nothing could prepare me for what I found - it was horrific and so upsetting."
Ms Jarvis added she has been unable to sleep after Hollie's death.
"I just hope someone will come forward to the RSPCA so we can find the person responsible," she added.
RSPCA inspector Adam Bailey said no suspects had been identified.
Mr Bailey said: "We do not know why or how Hollie was killed but we believe she was taken from the garden - where she was left as Andrea went to work - and killed elsewhere.
"There was no blood in the garden which suggests the attack happened elsewhere.
"The injuries sustained are horrendous and this has come as a huge shock to her owners."
The RSPCA is keen to trace anyone who may have information about what happened to Hollie or to anyone who saw anything suspicious to call the RSPCA appeals line on 0300 123 8018.