The court had earlier granted six months time for investigation, which will end on January 28.
According to CBI, there are 27 accused in the case and voluminous records and documents have to be perused for which more time was required.
The court had directed the CBI probe on a petition by some persons which made serious allegations against Revenue Department officials of colluding and conspiring with Salim Raj in forging and fabricating false documents and records for the purpose of defeating the title deeds of their lands at Kadakampally and Edapally.