17-year-old Md Israfil and 15-year-old Robeya Khatun were married about eight months ago
District and Sessions Judge Waheduzzaman Sikder handed down the verdict on Monday.
The two convicts Abdul Bashir and Nasir Uddin were present in court when the verdict was pronounced.
According to the case dossier, Tuhin’s body was found hanging from a tree near his home in Sunamganj’s Derai Upazila on Oct 14. Two knives were stuck to the child's stomach and the killers had cut off his ears and genital.
Police later arrested Abdul Bashir, Jamshed Ali, Mosabbir Ali, Nasir Uddin and Tuhin’s cousin in connection to the murder.