
Additional commissioner of Chittagong Metropolitan Police (CMP) Devdas Bhattacharya, said the man was arrested from Hathazari upazila of Chittagong on Wednesday morning.
The detained man is identified as--Abu Nasr alias Gunnu. He was the former member of Shibir.
Mitu was killed in a suspected militant attack in the southern city of Chittagong on Sunday morning.
She was stabbed and shot in the head by three men near her home in the port city while going to the GEC Intersection to drop her 6-year-old son to a bus stop for school.
TF/LY