Cheshire police have seized a dog that is reported to have ripped off the head of another dog during an attack.
A picture believed to be have been taken after the incident and circulated on social media allegedly shows a woman and the dog believed to be responsible walking off smeared with blood.
A Pomeranian dog died following the attack in the garden of a house in Warrington on Saturday.
Cheshire Police said they are examining the seized dog to determine its breed.
Chief Inspector Darren Hebden said: "This was a horrendous attack and was clearly very distressing for the owners to witness.
"I am aware of pictures that have been circulated on social media which will undoubtedly cause concern for the community but can I reassure people that we have now seized the offending dog so there is no risk to the general public.
"We will be speaking to the owners in due course and will do all we can to deal with the incident appropriately within the guidelines of the law."
Extra patrols will be in the area to talk to concerned residents and address any issues in the area.
Mother-of-three Gemma Antell, 30, of Fearnhead Lane, told The Warrington Guardian that her children are distraught following the death of their pet dog Elvis.
Ms Antell, whose mother-in-law was looking after the pet at the time, said the other dog had burst through the garden gate, snatched Elvis in its jaws and ripped his head off.
"It was like something out of a horror film, like it's not actually happened," she said.
"My children are distraught. It is the first thing they have had to lose and it's completely changed the way they see dogs as they are now terrified, which is very sad.
"At least it wasn't a child, but he was our loved family pet."