A RAB team arrested Abul Bashar, the launch master, in Hasnabad of Keraniganj on Monday morning, said Sujoy Sarkar, assistant director at the RAB Headquarters.
Earlier, a court ordered Mayur-2 owner Mosaddek Hanif Swad to jail on Sunday after his three-day remand ended.
On the morning of Jun 29, the ill-fated launch Morning Bird overturned after being hit by Moyur-2 near Shyambazar in the Buriganga River.
More than 50 passengers from Munshiganj swam ashore and the others were trapped, while 34 more were found dead after a search that lasted two days.
River police filed a case over the launch capsize, bringing charges of “negligent death” against seven people.