A mentally-imbalanced youth chopped his mother to death while she was offering prayers at Rajarhat upazila on Friday.
The deceased was identified as Mini Akter, 50, wife of Solaiman Ali of Panthabari village in the upazila.
Locals caught Montajul, 26, and handed him over to police.
They said Mini was offering Zohr prayers in her room when her son Montajul hacked her in the throat with an axe, killing her on the spot.
The locals said the youth became mentally imbalanced a few years back and he used to be tied with the rope. However his hands and legs were not tied during the incident.
Krishna Kumar Sarker, officer-in-charge of Rajarhat Police Station, said they arrested the youth and sent the body to hospital morgue for autopsy.