Earlier in February, the NIA had booked Dawood and others on charges of the UAPA act.
Mumbai court on Friday sent two associates of Dawood Ibrahim who were suspected in the D-company case, to 14-day judicial custody.
A special court sent the Mumbai residents' brothers Arif Abubakar Shaikh (59) and Shabbir Abubakar Shaikh (51), to NIA custody till May 20.
Earlier in February, the NIA had booked Dawood and others on charges of the Unlawful Activities (Prevention) (UAPA) Act. On Friday, it arrested Arif and Shabbir claiming that they were involved in activities of the gang in the western suburbs of Mumbai. They have also been booked under UAPA.