Police are questioning a 30-year-old man in Sunderland after a three-week-old baby was mauled to death by a family dog.
Reggie Young, from Falkland Road, is believed to have been attacked by the family's Patterdale terrier Tricky in the middle of the night.
Reggie's mother Maria Blacklin is understood to have been at a family event following a recent bereavement and returned home to what police described as a distressing scene.
Superintendent Gillian Mitchell, of Northumbria Police, said: "At approximately 4.15am we received a call to say that a small child had received a dog bite.
"Paramedics were called. Unfortunately, despite all their efforts, the child has died.
"Back at the house, there was a small terrier-type dog. That dog has been seized. Obviously we have concerns about the care of the child."
Reggie's father Ryan Young, a roofer, was arrested and questioned. The dog was removed from the home and will probably be destroyed.
Reggie's parents, described by neighbours as a caring couple, moved to the address two years ago and are thought to have four other children.
One neighbour, Denise Haley, 59, told the Sunderland Chronicle: "We are just thinking about Maria and we are really shocked and upset. Nothing like this has ever happened before. It is a total shock. We keep breaking down in tears."
A family member who did not wish to be identified said Reggie's mother never left her baby alone with the dog, which is said to be tiny and good-natured.
According to hospital statistics published in May 2015, in the last 12 months there were 7,227 hospital admissions following dog attacks, a rise of 6.5% on the previous year. There have been at least 21 canine-related fatalities over the last decade in the UK.