In a gruesome murder case, a teenaged boy killed four members of his family, including mother and sister, in Tripura's Dhalai district, police said on Sunday.

The police arrested accused Supriya Debnath,15, on Sunday when he went to the market to sell a duck. A police official said that Supriya killed his grandfather Badal Debnath, 70, mother Samita Debnath, 32, sister Suparna Debnath, 10, aunt Rekha Deb,42, with an axe when the victims were sleeping, late on Saturday night.

The horrific incident occurred at Durai Shib Bari village under Kamalpur police station in eastern Tripura's Dhalai district.

Further investigation is going on to ascertain the motive of the crime, the official added.