Dhaka, July 7 (UNB) – Detectives in a drive in Cumilla on Sunday arrested the prime suspect in the killing of six-year-old girl Samia Afrin Sayma after rape in Dhaka’s Wari area.   They arrested Harun-Or-Rashid, a painter by profession, from Darbardanga area in Titas upazila in Cumilla district.   Harun used to live in the same building where the victim’s family resides.