A man has been arrested after a two-month-old baby boy was airlifted to hospital with a head injury.
Paramedics and an air ambulance crew were called to an address in Steward Gate, Bamford, Derbyshire, at around 3.20pm on Thursday.
The baby was taken to hospital by air ambulance with a head injury.
A 37-year-old man was arrested in connection with the incident and remains in police custody.
"People living in the area will have seen a large number of emergency services staff, including police, throughout the afternoon," Derbyshire Police said in a statement.
"We understand that members of the public may be alarmed by the news but our investigation is in its very early stages. We will circulate any updates when appropriate to do so.
"Please be assured that our continued presence this evening is part of that ongoing investigation into the circumstances."