"These murders were done by Dr Rajesh Talwar and Dr Nupur Talwar," Kaul said.
Fourteen-year old Aarushi was found dead with her throat slit in her bedroom on May 16, 2008.
Hemraj was the primary suspect until his body was found on the terrace of the Talwars' Noida residence.
Initially, the CBI investigating team indicated the involvement of three domestic helps - Krishna, Raj Kumar and Vijay Mandal - but that was ruled out after the agency filed a closure report in December 2010.
On Tuesday, Kaul told the court that the crime scene had been dressed up.
He said the bedsheet on which Aarushi's body was found had no crease marks, and there was no blood spurt from the throat being slit.
Moreover, Hemraj's body had been covered with a cooler panel and the door to the terrace was locked from the stairs side.
The lawyer for the Talwars, Tanvir Ahmed Mir, reacted strongly to the accusation: "The IO's statements before the court stand contradictory to his final report where he stated there was insufficient evidence against Rajesh Talwar… Further, Nupur was never charged in this report."