The deceased were Jahanara, 40, wife of Saudi expatriate Giasuddin, their daughter Sharmin, 25, and Shimul, 27, a neighbour.
According to police sources, Giasuddin, who is now in Saudi, had long been in dispute with his brother Taher Miah over the ownership of a piece of land.
Assistant Superintendent of Police Raselur Rahman said Taher engaged in an altercation with the family members of Giasuddin around 9:15 pm.
Taher was furious and at one stage stormed the house of Giasuddin and slit the throats of Jahanara and her daughter Sharmin with a sharp weapon, killing them on the spot.
Taher also chopped Shimul with the weapon as he tried to prevent him. Jahanara’s son Sujat also got injured during the attack.
Later, locals sent Sharmin, Shimul and Sujat to Madhabpur Upazila Health Complex where doctors declared Sharmin and Shimul dead.
Meanwhile, Taher was caught by locals and they handed him over to police.
On Wednesday morning, when Taher was produced before the court, he admitted that he had killed the trio over land dispute and family feud, said Muktadhir Hossen, officer-in-charge of Madhabpur police station.