The Central Bureau of Investigation on Friday said the Nithari killings of women and children were "pre-meditated" and for sadistic pleasure. Investigations indicate that most of the gory murders were done by Surendra Koli, servant of the other key accused Moninder Singh Pandher.

"The probe so far indicates that it appeared that most of murders were committed by one of the two accused only but the investigation is still on," CBI Director Vijay Shankar told reporters in an informal gathering at the CBI headquarters.

While Shankar did not name the individual who had carried out maximum killings, sources in the agency said it was Koli, who had committed most of the spine-chilling murders.

To a specific question about the role of Pandher, Shankar only said, "The investigation is on and we are examining his direct and indirect role."

While terming Nithari killings as an "execptional case the world over" which shook the confidence of public, he said first chargesheet in this case would be filed before April.

"We have investigating all the 19 cases registered by the Uttar Pradesh police and I am satisfied with the pace of investigations. We should start filing chargesheets against the accused persons in next three months. It could be earlier as well," he said in an informal conversation with the media at the CBI headquarters in New Delhi on Friday.

He commended the Uttar Pradesh police for making foolproof arrangements in the Ghaziabad courts on Wednesday during the production of Pandher and Koli. During the last hearing the two accused were allegedly attacked by advocates and relatives of the missing children and the CBI had a tough time saving them. "Trouble came from unexpected quarters. We knew that there could be trouble therefore on that particular day we had sent as many as 30 of our men to escort the two accused," Shankar told newsmen.

He ruled out organ trade in the Nithari case. "So far during our investigations nothing has come up that would suggest that there was an organ trade racket involved in this most exceptional case of its own kind in the world," he said.

According to director CBI the bones and other remains of the bodies of the children have been airlifted to Hyderabad for conducting of DNA tests. "We have collected blood samples of the relatives of the missing children. But you have to remember that DNA tests have only a 50 per cent chance of succeeding. I am hopeful that our scientists would do a good job and ensure that this percentage goes higher," he said.

Though he did not rule out suspended cops of the Uttar Pradesh shielding Pandher, he said that the matter was still in preliminary investigation stage and it would be too early to jump to a conclusion. The average age of children who had been murdered by Koli and Pandher was between 5 to 21. "It appears that they derived sadistic pleasure out of killing the kidnapped children who had been sexually assaulted and then murdered in cold blood," Vijay Shankar said.

He talked about Uttar Pradesh police's claim that the accused were cannibals. He said that the findings of the Uttar Pradesh police also form part of the investigations. He complimented the media for doing a splendid job in this case.

"Nithari killings went on for a year and a half but there are no witnesses that would provide clinching evidence," he said. He ruled out the case being transferred out of Ghaziabad unless there is a court directive to do the same.

(With PTI Inputs)