A taped confession was allegedly made in prison by the Soham murderer, Ian Huntley, before his suicide attempt earlier this week.
Detectives are now studying the tape, which is believed to contain new information about the murders of Holly Wells and Jessica Chapman, both 10, in Soham four years ago.
Police are also investigating allegations that the tape was handed to the Wakefield Prison inmate who had given Huntley the anti-depressant drugs he used for his failed suicide.
The tape will be examined by police in West Yorkshire who are helping the prison service to investigate Huntley's suicide attempt - his second since his arrest. It will then be passed to detectives in Cambridgeshire who worked on the double murder case.
Huntley is now serving a life sentence of at least 40 years for murdering the two friends, who disappeared in August 2004. Their bodies were discovered in a ditch a fortnight later. Huntley, who was caretaker at the local school, and his girlfriend Maxine Carr, a teaching assistant, had denied any knowledge of their whereabouts. Huntley, however, had coaxed both girls inside his home, killed them and hidden their remains.
The precise circumstances of the killings still remain unclear and detectives will be hoping the tape could reveal crucial new details. Carr was convicted of perverting the course of justice, but has since been released from prison.Reuse content