"Mobile phones these days are very advanced with various features and this has to be looked into. It is a case of criminal conspiracy and forensic evidence is necessary. It is a primary evidence and thus we are opposing its release," CBI Prosecutor Akhilesh told Special Judge O P Saini.
Balwa's phones had been seized during his arrest.
The CBI, however, told the court that if Balwa requires various data stored in his phone, he can approach the investigating officer of the case.
Advocate Vijay Aggarwal, appearing for Balwa, argued if CBI considers his client's call details as evidence, it should get the same from the concerned telecom company instead and release his phones from their custody.
The court adjourned the hearing on Balwa's plea to March 29.
The Tihar jail superintendent, meanwhile, filed his reply to Balwa's allegations that the jail authorities did not allow his proper medical examination for his orthopaedic and gastric problems despite the court's order.
In his reply, the superintendent said Balwa was properly examined by doctors at Deen Dayal Upadhyay Hospital. The court allowed defreezing of former telecom secretary Siddharth Behura's bank accounts sealed by CBI.
The court's order came after CBI told the court that they do not have any objection to Behura's plea for defreezing of his two bank accounts.
Balwa was arrested from Mumbai on February 8 while Behura was arrested along with Raja and his former personal secretary R K Chandolia on February 2.
The four face CBI probe for their alleged roles in 2G spectrum scam under the Prevention of Corruption Act and the IPC, including those related to abuse of official positions, hatching criminal conspiracy, cheating, forgery in the process of the allocation of the spectrum.
