The dog which killed a five-year-old at a house on Merseyside is being tested for illegal drugs.
Ellie Lawrenson suffered fatal head and neck injuries
Ellie Lawrenson suffered severe injuries when she was savaged by her uncle's pit bull terrier-type dog at her grandmother's house in St Helens.
Toxicology tests will look for drugs in the dog's system - some animals are given steroids to build them up.
The one-year-old dog, called Rueben, was shot dead after the attack in which Ellie's grandmother was also hurt.
Jackie Simpson, 45, underwent surgery after trying to get hold of the animal.
A spokeswoman for Merseyside Police said that toxicology tests were a standard part of any post mortem examination.
She said: "Toxicology was carried out, which is routine in post mortems.
"We are looking at every aspect of the dog and its management as part of a full investigation."
The dog was owned by Ellie's uncle, 23-year-old Kiel Simpson, who was questioned by Merseyside Police last week, but was not arrested.
Owning a pit bull terrier, which is illegal under the 1991 Dangerous Dogs Act, carries a maximum sentence of six months imprisonment or a £5,000 fine.