"Court is convinced that to unearth the bigger conspiracy, thorough investigation in the matter with aid of custodial interrogation is required. Keeping in view the entire facts and circumstances of the case, the accused are remanded to police custody," Chief Metropolitan Magistrate Sanjeev Jain said.

Accused Mohd Saif, Zeeshan Ahmad, Mohd Shakeel, Zia-Ur-Rehman and Saqib Nissar were produced on completion of their 14 days' police remand.

Seeking fresh custodial interrogation of the suspected terrorists, public prosecutor Rajiv Mohan said, "To unearth the entire conspiracy, the accused persons may be required in other parts of the country to identify the co-conspirators or others involved in the heinous crime."

The prosecutor cited the complex nature of probe and its ramifications in other parts of the country as the grounds for their fresh custodial interrogation.

Saif and Zeeshan, who were sent to police remand in connection with the Karol Bagh blast, were on Saturday formally arrested in another case registered for carrying out blasts in Greater Kailash (part I) in south Delhi.

The other three -- Shakeel, Zia-Ur-Rehman and Saqib Nissar -- who were being interrogated by the police in connection their alleged involvement in Greater Kailash blast were formally arrested in the Karol Bagh blast case.