The deceased was identified as Monir Hossain, 48, while the injured as Yakub Sumon, 45, councilor of ward No 6 of Kishoreganj Municipality.
Police super Md Mashrukur Rahman Khaled said a gang of terrorist, wearing masks, attacked Yakub and his brother Monir around 9:30pm and hacked them indiscriminately, leaving them critically injured.
They were taken to Kishoreganj 250-bed Hospital first. As their conditions looked critical, they were sent to Mymensingh Medical College Hospital where doctors declared Monir dead around 10:30pm.
Besides, the terrorist vanalised their house at Akhra Bazar after the attack.
On information, police arrested six people along with locally-made arms from the spot.
However, the reason behind the attack could not be known, said the SP adding that the additional police have been deployed to avoid any untoward situation.