Magistrate S H Khutwad granted CBI custody of Vanzara till June 10, though the investigating officer Deputy Superintendent of Police G Kalaimani had asked for 14 days' remand.
Vanzara was arrested by CBI on Tuesday following his transfer to Sabarmati Central jail in Ahmedabad from Mumbai. He was in a Mumbai jail as an accused in the Sohrabuddin Shaikh encounter killing case of 2005. He is also an accused in the Tulsi Prajapati encounter killing case.
CBI lawyer T K Srivastava argued the agency needed to question him to find out the role of the intelligence agency which had provided inputs on the basis of which Gujarat police had claimed to have acted at the time.
"CBI also wants his custody for the recovery of weapons used during the encounter," Mr Srivastava said.
Mumbra-based Ishrat Jehan, Javed Shaikh alias Pranesh Pillai and alleged Pakistani nationals Zeeshan Johar and Amjad Ali Rana were killed in an encounter on the outskirts of the city on June 15, 2004.
Gujarat police claimed they were part of a conspiracy to assassinate Chief Minister Narendra Modi.
Following Ishrat's mother's petition, the Gujarat High Court constituted a Special Investigation Team (SIT) which concluded that the encounter was faked.
At Wednesday's hearing, opposing the remand plea, Mr Vanzara's lawyer V D Gajjar argued he was in jail since April 25, 2007 after he was arrested by Gujarat police in Sohrabuddin encounter case and SIT had interrogated him four times. "How can CBI discover or recover weapons as Vanzara is in jail for the past six years"?
Mr Gajjar also contended Mr Vanzara, who was the ACP with Ahmedabad city crime branch in 2004, was not in a position to receive intelligence inputs directly.
"K R Kaushik was Commissioner of Police for Ahmedabad city. Vanzara had no role to generate those inputs or no one shared inputs with him. And CBI has to date neither interrogeted nor arrested Kaushik," he said.
"After (former IPS officers) Julio Ribero and K P S Gill, Vanzara is the best anti-terrorist officer and a true fighter against terrorism in the country. While he has been in jail, whenever there is terror incident, police officers from other parts of the country visit him to seek guidance," Mr Gajjar said.