Surendra Koli, one of the two accused in the Nithari serial killings, shocked interrogators from the CBI when he told them he had again 'developed a desire to murder someone'.

Koli, who is being questioned along with co-accused Moninder Singh Pandher at an undisclosed location by the CBI,
said he had the desire to 'kill someone', senior officials involved in the probe said.

The officials said instructions had been given that no one should question Koli without 'taking proper precautions', including having armed guards present during the interrogation.

The CBI is taking the help of psychiatrists while questioning Koli, as his behaviour showed all the signs of a psychopath, the officials said. He is also being kept in handcuffs.

Koli and Pandher allegedly killed at least 15 women and children at the latter's home at Nithari in Noida.

Despite being handcuffed, Surendra often bursts into a violent fury, spewing cuss words, according to CBI sources.

Investigators have kept both the arrested accused -- Surendra and Moninder Singh Pandher -- separately while carrying out their interrogation.

"This has been done to avoid any sort of 'connivance' between the two," they said.

Also, their rooms were being kept free of any dangerous objects or materials with which they could attempt suicide, he said.

The official also stated that forensic tests on the 'biomaterials' collected were over and the CBI team was studying the findings before it could derive any conclusions - "This will take another six to seven days."

Also, on Surendra's disclosures, the bag of Deepika alias Payal, whose mobile led to the unravelling of the serial killings, was recovered from beneath his bed, the official added.

Last night the police had found an axe and polythene bags, resembling the type found containing skeletal remains dumped by the accused, from the D-5 killer house.

Meanwhile, the CBI team today raided the Faridabad 'den' of Neelam -- the 46-year-old 'madam' who managed Deepika alias Payal.

It also questioned about 10 policemen deployed at Nithari 'chowki' between 2004 (ever since the children started disappearing from Nithari village) and December last year in connection with the case.

On Thursday, the Noida police submitted all the materials it had collected during its searches to the CBI for investigations.

Meanwhile, the CBI appealed to the general public on Friday to desist from sharing information about the killings of women and children in Nithari without proper checking of the identity cards of the officers.

The appeal was issued when some people, posing as CBI officials, were seen roaming in Nithari and the camp office of
the probe agency seeking details from the victims and also assuring help in getting monetary relief.

The CBI, while alerting the public, said that they should share information only after verifiying the antecedents of the investigator.

With UNI inputs