An uncle of an 18-month-old girl who was attacked and killed by a dog in Crawley, West Sussex, is being held on suspicion of manslaughter.
Sussex Police said officers were called to reports of a girl suffering head injuries at a property in Cotton Walk, Broadfield, just after midday.
She was taken to East Surrey Hospital in Redhill, Surrey, but died shortly after arrival.
Sussex Police major crime branch has launched an investigation.
Det Ch Insp Trevor Bowles said: “It is very early in the investigation, but we are trying to establish how this tragedy occurred.”
A spokesman for Sussex Police said the dog was being securely held and officers were trying to determine its breed.