Merseyside Police has more dog legislation officers than any other force outside London, and for them Ellie Lawrenson's death was a call to arms.
Four breeds are banned under the Dangerous Dogs Act 1991
Soon after the incident on New Year's Day, the force launched a week-long dangerous dogs amnesty.
It gave owners a period of grace in which they could hand in illegal animals without being prosecuted.
It also provided an opportunity - taken by 644 people - to contact police about dogs they feared could be dangerous.
Assistant Chief Constable Helen King said owners must understand that ignorance is "not an excuse" for breaking the law.
"All dog owners should be aware of their responsibilities and must play their part in ensuring their animals are under control at all times," she said.
Pit bull terriers
"When a dog injures a child, or worse, the circumstances surrounding such an incident will be fully investigated. With the amount of publicity the issue of illegal dogs has received in recent times, ignorance is not an excuse.
"Those responsible should expect to face the consequences and may find themselves in court."
The Dangerous Dogs Act 1991 bans four breeds of dog - pit bull terriers, Japanese Tosas, the Dogo Argentinos and the Fila Brasileiros.
It also covers cross-breeds and any other dogs which appear "to be bred for fighting or to have the characteristics of a type bred for that purpose".
This is where controversy has arisen. The wording has led to many discussions in courts about what exact type a particular dog is - something which can confuse owners and police alike.
Mrs King said during the amnesty officers were able to reassure hundreds of owners that their animals were not illegal.
But in 48 cases specialist vets were called on to inspect the dogs to assess their characteristics.
Of those dogs that were found to be illegal, Merseyside Police have not said how many have since been destroyed.
The decision to put an animal down can only be made by the courts and most cases are still being processed.
If a banned dog is not put down, it will be placed on the Index of Exempted Dogs, which means it must be neutered, tattooed and micro-chipped and kept on a lead and muzzled when in a public place.
Merseyside Police are also currently prosecuting the owners of 47 pit bull-type dogs which were seized and suspected of being part of larger breeding operations.
Mrs King said: "These (prosecutions) are against people who are believed to be involved in supplying illegal dogs and against those who are buying them and keeping them as part of their criminal lifestyles.
"All of this work is helping to protect our communities and make Merseyside a safer place."
She said the force's sympathies were with Ellie's family, adding: "We cannot allow Ellie Lawrenson to have died in vain.
"I would ask our communities to support the work we are doing to help prevent a child ever being killed or even harmed in this way again."