Kuddus was employed as a night guard at the upazila Ansar and VDP office.
Locals spotted a plastic sack beside a motorbike in front of the Ansar office around 6:00am on Saturday. They at one stage checked it out and found a body inside.
Later, police came to the spot and recovered the body around 7:00pm.
Iftekhar said they gleaned some information from the detainee Ansar member. Things will be clear after investigation.
A source of Ghior police station said Kuddus had been in a loggerhead with the detainee over sharing bribe money collected from a recruitment of the paramilitary force. The murder might have been resulted from that feud.
Riaj Uddin, officer-in-charge of Ghior police station, said Shahinur initially confessed to his involvement with the murder.
The body bore injury marks from sharp weapons. A case will be filed soon and it will be investigated further.