Hussain was produced before District Judge H S Sharma by the NIA. The NIA team sought custodial interrogation of Hussain, saying they have to unearth the entire conspiracy which led to the blast.
Before the commencement of the hearing, the judge asked everybody present in the courtroom to go out.
"Only those persons will stand in the court whom I judge) will allow. Please vacate the court," the judge said.
Hussain was arrested on September 13 from Kishtwar in Jammu and Kashmir.
He is said to be a student of Islamia Faridia Higher Secondary School at Kishtwar and booked for criminal conspiracy for his alleged role in sending the terror mail from Jammu and Kashmir claiming responsibility for the Delhi High Court blast.
"We own responsibility of the blast at the High Court, Delhi. Our demand is that Afzal Guru's death sentence should be repealed immediately as we would target major High Courts and the Supreme Court of India," the terror mail had said.
The NIA has announced a reward money from Rs 10 lakh for anybody giving information about the perpetrators of the blast.
Fifteen people were killed and over 70 injured in the blast outside the Delhi High Court. The probe was handed over to the NIA.