Claiming it had made significant progress in its probe into the killing of Sohrabuddin Sheikh in a fake encounter, the police on Saturday gained custody of three senior IPS officials arrested in the case for three more days to investigate the murder of his wife Kausar Bi.

Controversial IPS official D G Vanzara, however, claimed that the charges against him were interpolation and concocted. A calm, composed and unruffled Vanzara smiled at reporters in the court when he was brought there by the CID.

"We have made significant progress in the case. We have found out where Kausar Bi was killed," Public Prosecutor N H Saini told the court that extended the police remand for the three officials but did not give details.

"This is a serious crime," he said, noting that the accused -- DIG (Border Range) Vanzara, SP Rajkumar Pandiyan of Gujarat's intelligence wing and SP Dineshkumar M N from Rajasthan -- were high-profile police officers.

Producing the three officials before Chief Metropolitan Magistrate K J Upadhyaya, the CID (Crime) sought further custody of the accused as its probe into the motive for the murder of Kausar Bi was incomplete. The court extended their remand till May 8.

"We still need to find out the motive behind Kausar Bi's murder," Saini said.

He told the judge the CID had made good use of the four-day remand granted earlier by the court and made significant progress in the case.

Vanzara also claimed allegations leveled against him in connection with Kausar Bi's death were "concocted". The Gujarat government has admitted that Kausar was killed and her body burnt.