A week-long dangerous dogs amnesty is beginning on Merseyside, allowing owners to hand in their animals without being prosecuted.
Dogs will be collected by trained officers
Four types of animal are banned under the Dangerous Dogs Act 1991 - pit bull terriers, the Japanese Tosa, the Dogo Argentino and the Fila Brazileiro.
Animals can be handed in between 0700 GMT, and midnight next Tuesday.
The amnesty follows the death of five-year-old Ellie Lawrenson, mauled to death by a dog on New Year's Day.
Ellie was killed by her uncle's pit bull terrier at her grandmother's house in St Helens.
The one-year-old dog, called Rueben, was shot dead after the attack in which Ellie's grandmother was also hurt.
Ellie's uncle, 23-year-old Kiel Simpson, was questioned over the attack but not arrested.
Ellie Lawrenson was mauled to death on New Year's Day
Merseyside Police have said it is up to dog owners to contact them to arrange for dogs to be collected from their homes.
If the owner of an illegal dog chooses not to hand it over voluntarily then the dog will be seized and owners could face a £5,000 fine and six months imprisonment.
The court will then decide if the dog is to be destroyed.
If the dog is not put down, it will be placed on the Index of Exempted Dogs.
However, it will have to be neutered, tattooed and micro-chipped in addition to being kept on a lead and muzzled when in a public place.
Also, the dog cannot be left in possession or control of anybody under the age of 16.
Officers have said the main problem on Merseyside is with pit-bull terrier types, but all illegal dogs will be collected.
Chief Constable Bernard Hogan-Howe said: "We want you to hand in illegal dogs, including the pit bull and pit bull type.
"You may not agree with the hand-in but I am sure all parents will want to prioritise the safety of their children above the affection for their dogs."