The 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 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 Monday.

Mr. Raigar is being questioned at Gandhinagar, they said.

Mr. 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 encounter case before the probe was transferred to the CBI by the Supreme Court in January this year. Both the former cops were questioned by the CBI in May this year.

The CBI on Sunday arrested former Gujarat minister of State for home Amit Shah on 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.