text: Six-month-old Molly-Mae Wotherspoon was fatally attacked by an American pit bull named Bruiser at a house in Daventry in October 2014.
  Mother Claire Riley, 23, and grandmother Susan Aucott, 55, are currently in prison in connection with the death.
  Northamptonshire Police said it had "overhauled" its dangerous dogs policy.
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  The serious case review highlighted a number of failings.
  The report states Riley took Bruiser - one of two dogs in her home - to a vet in January 2014 when Riley was pregnant.
  The vet voiced his concerns about the fact the animal was an illegal breed to the RSPCA, which made a referral to the police.
  The report said the force failed to act on these concerns.
  Det Supt Steve Lingley, head of safeguarding at Northamptonshire Police, welcome the report's findings on what he said was "a very challenging case on a number of levels".
  "Within weeks of the tragedy," he said, "Northamptonshire Police had carried out a complete overhaul of its response policy to dangerous dogs."
  Keith Makin, chairman of the  Northamptonshire Safeguarding Children Board (NSCB), recommended "greater curiosity" about family pets amongst health workers.
  He also called for "all police officers to be made aware through safeguarding training of the dangers which aggressive dogs pose to young children".
  The report stated: "The dog was so fierce that a vet had earlier refused to examine it for an illness unless it was first fully sedated."
  It also said that while Riley was "fully aware that her own mother had alcohol-related problems" she went out for evenings leaving her in "sole charge of the baby while the dogs were in the house".
  The report concluded "although some poor practice has been highlighted" by the board's inquiries, there was nothing which suggested "any single professional could, or should, have prevented" Molly-Mae's death.
target: Police failed to act on concerns raised about an illegal dog before it killed a baby girl, a report has found.