The two accused of Darbhanga Railway Station parcel blast case Haji Salim and his son Kafil were produced in Patna NIA court today.
The court ordered custody to the duo to NIA till 10th of July.
The NIA arrested father and son from Kairana in Shamli district of Uttar Pradesh on Friday.
Earlier, the court had ordered seven-day Judicial Custody to Mohammad Nasir Khan and his brother Imran Khan with alleged Lashkar-e-Taiba links in the same case.
They are being interrogated for their alleged involvement in the Darbhanga Railway Station parcel blast case.
Sources said, NIA has sought assistance from the Enforcement Directorate to know about bank transaction and funding of accused.
The two brothers were arrested in Hyderabad on 30th of June.
A parcel containing women’s clothing, which was sent via train from Secunderabad, had exploded while it was being unloaded on Platform No. 1 of the Darbhanga Station on 17th of June.