Bulbul Ahmed, a student at Shahjalal University of Science and Technology (SUST), was killed by muggers.
Ajbahar Ali Sheikh, Deputy Commissioner of Sylhet Metropolitan Police (SMP), said this at a press briefing at Jalalabad Police Station in Sylhet on Wednesday.
The officer said that after questioning three arrestees, they were able to ascertain that the incident was simply a mugging.
Earlier on Monday evening, Bulbul, a third-year student of the Public Administration Department at SUST, was killed beside Shaheed Minar of the university adjacent to Gazi-Kalu-Tila (hummock).
Ishfakul Hossain, the university's registrar, filed a murder case with the Jalalabad Police Station that evening.
Police arrested three suspects: Abul Hossain, 19, Kamrul Ahmed, 29, and Mohammad Hasan, 19 till Tuesday.