Police have arrested four people in connection with the murder of Police Super Babul Akter`s wife Mahmuda Khanam Mitu. DIG of Police Bureau of Investigation (PIB) Nonoj Kumar Majumdar confirmed this on Monday noon. Unidentified miscreants gunned down Mahmuda Khanam Mitu at the city`s GEC intersection on Sunday morning while she went there to drop her son, Mahir Akhter, 7, for a bus to Chittagong Cantonment Public School and College.