The Supreme Court today upheld the death sentence to Nithari serial killer Surinder Koli for murdering 14-year-old Rimpa Haldar, one of his victims in the serial rape-cum-killing episode six years back, saying the case was "horrifying" and "barbaric".

A bench of justices Markandey Katju and Gyan Sudha Misra confirmed the death sentence to 39-year-old Koli, who has also been awarded capital punishment by the trial court in three other cases of rape and killing of young women and children in Nithari village near Noida on the outskirts of the national capital.

A total of 16 cases were registered against Koli. His businessmen employer Moninder Singh Pandher was sentenced to death in Rimpa Haldar case but he was acquitted by the Allahabad High Court. 54-year-old Pandher is facing trial in other cases.

"In our opinion this case falls in the rarest of rare category and no mercy can be shown to him," the bench said, while confirming Koli's death sentence, which earlier had been endorsed by the Allahabad High Court.

Relying upon the Koli's confessional statement, in which he had given "graphic details" of how he used to allure and kill young girls in Noida, the court said, "The confessions had been made voluntarily before the magistrate and there is no defect in it."

The bench confirmed Koli's death sentence, first awarded by CBI special court at Ghaziabad and later endorsed by the high court, dismissing his appeal in one of the first of the 16 cases.

This case pertains to the rape and murder of a minor girl Rimpa Haldar.

While confirming Koli's death sentence, the apex court kept pending with itself the CBI appeal against acquittal of Pandher, saying any order passed against him or in his favour can have a bearing on remaining cases which are at the trial stage.

The bench said before deciding the CBI's appeal, it would wait for the outcome of the trial of other cases in which Pandher is accused along with his servant Koli.

Koli was sentenced to death along with Pandher by the Ghaziabad court on February 13, 2009, and the Allahabad High Court had confirmed Koli's death sentence on September 11, 2009 while acquitting Pandher of the charges. Aggrieved, victim Rimpa's father Anil Haldar had filed the appeal challenging Pandher's acquittal and sought restoration of the death sentence awarded to him by the sessions court.

Rimpa had gone missing from her home in the neighbourhood of Pandher's Noida residence in early 2005.

The case of Nithari serial killings came to light toward the fag end of December 2006, following discovery of human remains from a drain behind Pandher's house in Noida. A subsequent and thorough search of the drain had kept yielding human remains and skeletons for over a week.

The case was initially probed by the Noida police but was later handed over to the CBI, which had registered a total of 19 FIRs related to the serial killing.