Children were made to perform "sexual activities" with each other - and animals - at a hotel, a family court judge has concluded.
Social workers with responsibility for child welfare had asked Judge Hilary Watson to investigate a series of allegations made by a number of children.
The judge has made a series of findings of facts after analysing evidence at a family court hearing in Coventry.
She said four children aged between eight and 14 were at the centre of her inquiries, and allegations had been made about a man they knew.
No one was identified in a written ruling.
Judge Watson said the local authority with responsibility for the children was Coventry City Council.
She said police were involved but she did not reveal whether anyone has been charged with any offence.
Children spoke of travelling to Birmingham on a bus and indicated that the hotel was in the city.
They also indicated that activities had been recorded on video.
Judge Watson said some of the "suggestions" might seem "fantastical", but concluded they were probably a "grim reality".
Judge Watson said: "In my judgment, the children are telling the truth when they describe being taken ... to a hotel where they had wine and tablets and were made to perform sexual acts watched by other people.
"It is suggested that the accounts are not to be believed because the children report sexual activity with (a) dog and other animals. A rabbit was described as being frightened ... and running off.
"Such suggestions might seem fantastical but become a grim reality when seen in the context of my findings that the children have been made to perform sexual activities with each other for the sexual gratification of (the man), for the video camera, and for other people."
The judge added: "It is highly probable that the children were made to perform sexual acts on animals."