"After seizing of mobile, if the accused says that he will not give his (phone's) password and tells you to go to hell, this is called non-cooperation," Additional Solicitor General (ASG) Tushar Mehta, who appeared for the CBI, said.
Mehta also submitted a sealed envelope to the court and refrained from reading the material aloud.
The custody of Karti, who was arrested on February 28 and sent to a five-day remand till March 6, was further extended by three days till March 9.
The CBI on March 4 took the former minister's son to Mumbai to confront former Directors of INX Media Ltd., Indrani and Peter Mukherjea.
Mehta said Indrani Mukherjea's statement was "one of the evidence for the probe agency, but not the sole one".
However, Karti's lawyer A. Singhvi countered the CBI claim of non-cooperation and said he (Karti) was not in the custody to answer what the CBI wanted to hear.
"If I am silent that does not mean an evasive and non-cooperative (behaviour)," Singhvi argued.
He added the CBI did not give any valid reason but kept repeating orally that they had to interrogate Karti.
The lawyer also asserted the CBI had not given a single ground or wrote any reason in its application for further remand.
"Karti Chidambaram only had a 25-minute long confrontation with Indrani, and around two-hour-long interrogation in the last five days. There is no need for further custody," he said.
The agency however said the presence of the accused was needed in order to serve some important and specific purposes connected with the completion of investigation in the case.
It said the agency during the custodial interrogation so far was able to gather some important information even though Karti had remained evasive while answering the routine questions.(ANI)