Noida: Moninder Singh Pandher and Surender Koli, the main suspects in the Nithari serial killings, were today brought back from Gandhinagar in Gujarat after subjecting them to narcoanalysis test.

The duo reached here this morning and are being kept by the Noida police at an undisclosed location. They will be produced in a local court tomorrow on expiry of their police remand.

Police also said they are in the process of handing over documents, including the preliminary investigation report in the case to the CBI, which began its probe into the serial killings yesterday after registering 19 cases.

The CBI and the forensic team are likely to visit the scene of crime today, the sources added.

Meanwhile a bone, found by a villager, became the centre of attention in Nithari village in this industrial township this morning.

It was found lying near a drain outside Pandher's D-5 residence. But it was not sure whether it belonged to a human being or animal.

Police had on December 29 receovered skulls and human remains from a drain behind Pandher's residence unearthing the serial killing of children and woman allegeldly by him and domestic help Koli.