CBI has summoned two retired IPS officers, who had at one point of time headed the probe into the Sohrabuddin Sheikh fake encounter case as chiefs of state CID, and questioned one of them.

G C Raigar and O P Mathur, who have already been questioned earlier by the CBI in connection with the fake encounter of Sohrabuddin and killing of his wife Kausarbi in November 2005, have been called for further questioning, sources in the CBI said today.

Raigar is being questioned at Gandhinagar, they said.

Mathur is presently head of Raksha Shakti University recently set up by the state government.

The two retired IPS officers were heading the state CID which had earlier investigated the Sohrabuddin fake encounter case before the probe was transfered to the CBI by the Supreme Court in January this year.

Both the former cops were questioned by the CBI in May this year.

CBI yesterday arrested former Gujarat minister of state for home Amit Shah on the charges of criminal conspiracy, murder, kidnapping and extortion.

The central agency, after taking over the investigation in the case, has also arrested IPS officer Abhay Chudasama, a key conspirator in the case.

CBI had alleged that Chudasama used to run an extortion racket along with Sohrabuddin.

Senior police officers of the Gujarat police have also been questioned by the CBI since it registered a fresh FIR in the encounter of Sohrabuddin and killing of his wife Kausar bi.

Those questioned by CBI include Geetha Johri who was the investigating officer when the case was being probed by the state CID.

The CBI has also recorded statements of the then DIG-Crime Rajneesh Rai, who had arrested three IPS officers D G Vanzara, Rajkumar Pandian and Dinesh M N, considered to be main conspirators.

They have also questioned IPS officer G L Singhal, presently with the state's Anti-Terrorist Squad (ATS). Singhal was Gandinagar SP when the encounter took place.

The earlier probe by CID had led to the arrest of 14 policemen including three IPS officers - Vanzara, Pandian of Gujarat cadre and Dinesh M N of Rajasthan cadre for staging a fake encounter of Sohrabuddin.

While handing over the probe of the case to CBI the Supreme Court had minced no words in expressing displeasure at the failure of the Gujarat police's special investigation team headed by Inspector General of Police Geetha Johri to identify the seven Andhra Pradesh police personnel who assisted the local police in the encounter.