A 13-year-old teenage boy was tortured to death after being tied to a tree over a trifling matter in Eidgaon upazila of Cox’s Bazar district on Sunday.

The deceased was identified as Mohammad Sazzad, son of Nurul Huda of Uttar Sat Jhulakata village in the upazila.

Mahfuzul Islam, superintendent of Cox’s Bazar Police, said a complaint has been lodged with Eidgaon Police.

Police registered a murder case following the complaint later.

Police also arrested Mohammad Alam, the prime accused in the case in the small hours of Monday. The others accused were identified as Abdus Salam alias Tuilla, 55, son of Saber Ahmed, Minuara Begum, 40, wife of Abdus Salam and Nurul Azim alias Kalu, 15, son of Abdus Salam.

Sazzad had a quarrel with the son of Alam and he tortured Sazzad over the issue, he said. “However, police are investigating the incident.”

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According to the complaint, a group of miscreants dragged and picked up Sazzad to East Isakhali village from in front of a tea shop around 3 pm on Saturday.

Later, a group of musclemen led by Alam, 30, beat Sazzad up mercilessly after tying him up to a betel-nut tree.

When Sazzad became unconscious, they left him abandoned, assuming that he was dead.

On information, Sazzad’s father Nurul rescued him and gave him first aid. After seeing the deteriorated condition of Sazzad, they took him to Eidgaon Medical Hospital where the doctors declared him dead at 6 pm on Sunday.

Police sent the body to the hospital morgue for autopsy.

Efforts are on to arrest other culprits, said SP Mahfuzul.