An old man was allegedly beaten to death in Rangpur's Pirgachha upazila following a dispute over his wife's alleged extramarital relationship, police said.

The deceased was identified as Chan Mia, 42, a resident of Chhoto Digtari village under Kandi union in the upazila.

Police arrested the prime accused, Mahfuz Ahmed Mithun, 35, and sent him to jail through a court on Saturday, said Sub-Inspector (SI) Shamim Mondal of Pirgachha Police Station.

According to police and local sources, Chan Mia married Mukti Begum, also known as Mukta, around 20 years ago. The couple have a son and a daughter. Chan Mia had long been working at a garment factory in Dhaka.

Locals alleged that during his absence, Mukti developed an extramarital relationship with their neighbour, Mahfuz Ahmed Mithun.

After the relationship became known, Mukti and Mithun reportedly moved to a neighbouring upazila and began living there. The issue had led to tensions between the two sides for some time.

According to the complaint, Chan Mia encountered Mithun at around 9 pm on Friday, triggering an argument. Mithun allegedly assaulted Chan Mia during the altercation.

When locals rushed to the scene after hearing Chan Mia's cries for help, Mithun took shelter at a nearby house. He later returned and allegedly attacked Chan Mia again, beating him severely. Chan Mia died at the scene, according to the complaint.

Alam Mia, the victim's nephew, filed a murder case with Pirgachha Police Station, accusing Mukti Begum, Mahfuz Ahmed Mithun and several unidentified individuals.

SI Shamim Mondal said Mithun had been produced before a court and sent to jail, while efforts were underway to arrest the remaining accused.

The body was sent to Rangpur Medical College Hospital morgue for an autopsy, he added.