Detectives are trying to trace anyone with connections to a farm where children from South Yorkshire were placed in foster care - following an allegation of a serious offence.
Youngsters from Derbyshire, Sheffield and Rotherham were placed at Middle Farm, Duckmanton, between 1963 and 1974.
A Derbyshire Police spokeswoman said: “Derbyshire police are appealing to anyone who had connections with Middle Farm in Duckmanton in the 1960s to contact them.
“The investigation is at an early stage.
“People have been interviewed by detectives but no one has been arrested.
“Officers are trying to develop an understanding of the environment and care given there.”