A brother and sister were hacked to death, and five others of the same family were injured in a clash over "planting saplings" in a disputed land.
The deceased were identified as Mahmudul Hasan Alamgir, 32, and Nadira Akter, 22.
Police have arrested two people in connection with the murders. Tension prevailed in the area over the incident.
The incident took place at Uttar Kurimara village in the Sahedal union of Kishoreganj's Hossainpur upazila this morning.
According to police, two sides got into an argument on Wednesday over planting saplings on a disputed land.
Following the incident, Mahmudul and his family members were attacked with locally-made weapons this morning.
Mahmudul died on the spot. Nadira, Salman (21), Saima Akter (48), Humayun Kabir (28), and Shamsuddin (60) were admitted to Shaheed Syed Nazrul Islam Medical College Hospital.
Later, the duty doctor sent Nadira to Mymensingh Medical College Hospital for better treatment, where she succumbed to her injuries.
Kishoreganj Superintendent of Police Mohammad Rasel Sheikh visited the spot following the incident.
Hossainpur Police Station OC Md Asaduzzaman Titu said the bodies of the deceased were sent to Kishoreganj Modern Sadar Hospital morgue for autopsy.
Police operation is on to arrest others involved in the murders, he added.