Police and public prosecutors in Dessau-Roßlau said on Sunday a police officer called to the incident shot the animal dead in order to get to the child, but the boy was already dead.
He was being looked after by a 76-year-old woman – a relative according to local radio reports - who had taken in two Rottweilers. The other dog was taken to an animal home.
Saxony-Anhalt state Interior Minister Holder Hövelmann said he was shocked by the incident, saying on Sunday that the boy's death showed again the danger of aggressive dogs. He said the exact circumstances should be examined before any conclusions were drawn.
Laws controlling the ownership of dangerous dogs must be fully applied he said, adding that the investigation into the boy's death would be expected to examine whether this was the case.