Police have named a three-year-old boy who was killed in a dog attack as Daniel John Twigg.
Paramedics were called to Carr Lane in Milnrow near Rochdale on Sunday afternoon.
Daniel was taken to hospital but died a short time later.
A 48-year-old man was arrested after he handed himself in and is being questioned, police said.
Officers have established that Daniel was with a number of dogs in an outdoor area surrounding his home before being discovered with serious injuries.
Several dogs were seized, one of which, a Cane Corso, has been humanely destroyed.
Officers said they were continuing to investigate and “reviewing other incidents of note”.
“Though a man is in custody, our investigation is very much ongoing to establish the full circumstances surrounding this incident and ensure any criminal offences in relation to Sunday’s incident are identified and prosecutions sought,” said Detective Chief Inspector Gina Brennand.
“Meanwhile, officers are also reviewing other incidents of note. Due to previous contact, GMP’s Professional Standards Branch has referred the incident for review by the Independent Office for Police Conduct.”
DCI Brennand asked the public and media “to refrain from speculating whilst we complete our investigation and any subsequent proceedings are concluded”.
Anyone with information should call 0161 856 7386, quoting Operation Guernsey. Or to remain anonymous, they can call Crimestoppers on 0800 555 111.