National Investigation Agency (NIA) Special Judge H.S. Sharma, during the in-camera proceedings, found prima facie evidence against Wasim Akram Malik, sources said.
The court found sufficient evidence against Malik under penal provisions dealing with criminal conspiracy, murder and attempt to murder and various terror charges, the sources said.
The court fixed Sep 18 for order on the framing of charges against Malik, who is in judicial custody.
The NIA in March filed a charge sheet against six accused, including a minor. Malik and another accused, Amir Abbas Dev, were arrested in September 2011.
Amir Abbas Dev has turned approver in the case and is in judicial custody.
The other accused in the case are Malik's brother and alleged Hizbul Mujahideen terrorist Junaid Akram Malik, Shakir Hussain Seikh alias Chota Hafiz and Amir Kamal. They are on the run.
"Wasim Malik, an avid internet user, is one of those leaderless jehadis who conspired with the terrorists of Hizbul Mujahideen and other outfits and executed this cowardly and inhuman terrorist action," the NIA said.
Fifteen people were killed and 79 others injured in the Sep 7, 2011 blast outside Gate No.5 of the high court complex.