A 20-year-old Birmingham nursery worker has been arrested on suspicion of child abuse, West Midlands Police have said.
Detectives from the force's Public Protection Department and local police officers arrested the man at his home in Nechells in the early hours of Wednesday.
He was employed as a nursery assistant at the Little Stars Nursery, Nechells Park Road. The nursery was closed today.
As part of the investigation, a number of items - including a computer - have been seized. These items are currently being examined by be specialist investigators.
A joint investigation is now being carried out by West Midlands Police and Birmingham City Council Children's Services.
Parents and guardians of children registered at the nursery are being contacted by police and the city council.
Assistant Chief Constable Anil Patani, who is leading the enquiry, said: "The investigation is in its very early stages, however we believe that we have identified one victim who we believe attends the nursery.
"The family of this child have been told and police are supporting them at this very difficult time.
"As the investigation continues, we will update families with children at the nursery at the earliest possible opportunity."
A meeting will be held for parents with officers and council officials providing an update on the investigation.
An advice line for parents has been opened with specialist staff on hand. The number is 0121 675 4806.
The man arrested remains in police custody and is currently helping police with their inquiries.