A five-year-old girl has been killed and her grandmother seriously injured by a pit bull terrier at their family home on Merseyside.
Ellie was found bleeding to death in the living room
Ellie Lawrenson was found bleeding to death in the living room of the house in St Helens shortly before 0430 GMT.
Her grandmother, Jackie Simpson, 45, who is recovering in hospital, managed to lock the dog outside.
The owner, believed to be Ellie's uncle, had been warned in June about the dog's behaviour.
The pit bull terrier was destroyed by police immediately after the attack at the property in Knowles House Avenue, Eccleston.
Ms Simpson, who shared the home with Ellie's aunt and uncle, was bitten on her arms and legs.
Her injuries are described as "serious but not life threatening". Police said she may have to undergo surgery at Whiston Hospital where she is being treated.
Superintendent Jon Ward, operational manager for the St Helens region, said: "This is such a tragic incident.
"We attended the scene, by which stage the dog had been shut away down the side entrance of the house.
"When officers arrived it became apparent from a very early stage that the girl had tragically died as a result of the attack.
"The ambulance service did what it could for her but unfortunately she died at the scene."
Police dog handlers who arrived minutes later, decided the dog, called Reuben, had to be shot as soon as possible.
Police are investigating whether fireworks frightened the dog
Mr Ward added: "They made a decision as to whether it was safe to control the dog and seize and safely remove it.
"The assessment was that that couldn't be done safely so the dog was humanely destroyed at the scene around 5.40am this morning."
Detectives understand Ellie's parents were not in the house at the time of the attack.
Police believe Ellie's parents went out to celebrate New Year's Eve, leaving Ellie with her grandmother, and when they returned Ellie asked to stay there.
They are then thought to have left the property at about 0340 GMT, shortly before the attack.
According to police, Ellie's uncle was not at home when the attack happened.
However, Mr Ward said Ellie regularly stayed at her grandmother's house so police believe she knew the dog well.
A large part of Knowles House Avenue was cordoned off with police tape on Monday afternoon as forensic officers continued to examine the end-of-terrace house where Ellie was mauled.
DANGEROUS DOGS ACT 1991
Drafted at speed after string of dog attacks, and much-criticised
Bans breeding and sale/exchange of pit bull terrier, Japanese tosa, Dogo Argentino, and Fila Brasileiro
Also bans all dogs "appearing... to be bred for fighting or to have the characteristics of a type bred for that purpose"
Also covers any dog "dangerously out of control"
But this applies only to public property, or private property where the dog is not permitted
Out-of-control dogs can be seized and destroyed, and the owners faces a fine or up to six months in prison. If the dog injures someone, that can be up to two years.
A white and yellow forensic tent was attached to the front door of the property which is believed to be owned by Ellie's great-grandmother.
A police spokeswoman said Ellie's body was removed from the house at about1400 GMT.
She confirmed that several members of Ellie's family had arrived at the property in the morning wanting to see her body.
"They were obviously distressed and distraught at not being able to see Ellie, but we couldn't let them in while the body was still in situ and while forensic science officers were still at the scene.
"There was some shouting, there are a lot of high emotions flying around," she said.
Dorothy Watkinson who lives near the family home told BBC News that Ellie was used to dealing with the dog.
"I've seen her at the gateway with it, stroking it. It never turned on her like that."
Supt Ward said: "This is such a tragic incident. When a child loses her life in such circumstances, it has an effect on the whole community."
He added that the safety of the public and police officers was paramount and in such circumstances "we were left with no other option but to have the animal destroyed quickly and humanely."
He added said police would be looking into whether any offence had been committed under the Dangerous Dogs Act.