Detectives launched an inquiry after accusations of violent and sexual abuse were made against former workers at care homes going back to the 1960s.

The investigation uncovered 150 people claiming to be victims of abuse or witnesses to it.

The NSPCC has received 63 calls from people claiming they were abused in Jersey care homes, 27 of which have been referred to detectives.

As a result, police searched a former children's home Haut de la Garenne where they discovered a child's skull on Saturday and are now searching six more sites at the building now used as a youth hostel.

The search is centred on a bricked up cellar where a specialist sniffer dog from South Yorkshire, springer spaniel Eddie, found the body of a child under several inches of concrete. Eddie has identified a further six suspicious areas.

Eddie, who works with South Yorkshire Police as an "enhanced victim recovery dog" was still at the building last night along with Keela, another Yorkshire springer spaniel trained to detect blood traces.

Eddie is said to have picked up traces of missing Madeleine McCann in the back of a car which her parents hired five weeks after she disappeared.

Jersey's Deputy Police Chief Lenny Harper said: "Part of the inquiry will be the fact that a lot of the victims tried to report their assaults but for some reason or another they were not dealt with as they should be."

The state's former health minister, Senator Stuart Seyvret, has accused the government of a cover-up.

Jersey's Chief Minister, Senator Frank Walker, said they would help the police investigation, including any allegations of a cover-up. "If anyone is found guilty they would be arrested and prosecuted in exactly the same way as the people who perpetrated these evil crimes," he said.

Police said that records of children at Haut de la Garenne are "patchy" and those who died in care may have been reported as runaways.

It is understood that children at the home were forced into solitary confinement and, when asked if the cellar was used for this, Mr Harper declined to comment. He said they have names of missing children but would not comment on how many or who. The main focus of the investigation centred on allegations in the 1970s and 1980s.