A one-year-old boy has died after being attacked by a pet rottweiler at his grandparents' home, police have said.
Archie-Lee Hirst died from multiple injuries
Archie-Lee Andrew Hirst was snatched from his seven-year-old aunt's arms in the yard of the house in Chald Lane, Wakefield, West Yorkshire, on Friday.
He was taken to hospital with serious injuries but died later.
The "seven to 10 stone" dog was shot at the scene by a police marksman. It was destroyed to ensure the safety of others there, a police spokesman said.
The boy's family, including his teenage mother, are now receiving support from specially-trained officers, he said.
Det Supt Steve Payne, from West Yorkshire Police, said the boy was staying with his grandparents during the Christmas holidays.
He said: "What we know at this time is that the dog was a family pet, a two-and-a-half year old female rottweiler, which the family had owned for about six months.
"Although the dog lived in the yard of the premises, it had interacted with members of the family including children, and another dog and cat at the house, and had shown no previous signs of any aggression."
Archie-Lee is at grandparents' Wakefield home
Aunt, 16, is looking after him and two sisters, six and seven
Seven-year-old takes Archie to kitchen to stroke the dog
Dog snatches Archie, takes him into yard and attacks him
The seven-year-old goes upstairs to tell the 16-year-old
The 16-year-old strikes the dog several times but cannot separate it from Archie
1530 GMT: Aunt phones 999
1536 GMT: Paramedics arrive
1539 GMT: Armed police arrive
Dog shot by police marksman
Archie-Lee dies in hospital
Mr Payne said one of the boy's aunts, aged 16, was caring for him and her two sisters, aged six and seven, in the house.
The 16-year-old girl was upstairs when the seven-year-old carried the baby outside to stroke the dog.
Mr Payne said: "Without any warning, the dog snatched the baby from the youngster's arms and carried him into the yard."
He said the 16-year-old tried to rescue the baby but was unable to do so, despite striking the dog several times.
Paramedics and police arrived within six minutes following an emergency call to police at 1530 GMT, he said.
The baby was taken to Pinderfields General Infirmary where he was pronounced dead.
The boy's parents were at a nearby property at the time.
A post-mortem examination has shown Archie-Lee died from multiple injuries consistent with a dog attack.
The death follows the unlawful killing of five-year-old Ellie Lawrenson who was killed by her uncle's dog in St Helen's on New Year's Day 2007.
The illegal pit bull terrier called Reuben attacked Ellie at the home of her grandmother, Jackie Simpson, who was later found not guilty of manslaughter through gross negligence.
Ellie's uncle Kiel Simpson, 24, was jailed for eight weeks at Liverpool Magistrates' Court in May after admitting owning a dog banned under the Dangerous Dogs Act 1991.
Chris Window, from the Rottweiler Club, said it was very uncommon for attacks of this nature to take place.
But he said young children should never be left alone with any breed of large dog.
"All breeds of dogs are animals. They do revert to animal instincts. If a dog is confronted with a situation they are not used to, they can react unexpectedly."