Abbas Ali, 50, and his son, 20-year-old Aiya, died when an Indian truck with registration plate WB 194807 hit their motorcycle.
Aiya died on the spot while Abbas died on the way to Neuro Hospital, according to police.
Police has taken control of both vehicles.
Meanwhile, Manoj Mukti, a member of Janatantrik Tarai Mukti Morcha (Rajan group) talk team, was critically injured in an accident.
According to JTMM, Mukti and Naseem Rain were seriously injured on the way to Janakpur from Laxmipur of Dhanusha on an Indian vehicle.
Both are being treated at the Zonal Hospital in Janakpur.
Meanwhile ,a woman died in a road accident at Itahari of Sunsari district on Tuesday morning, according to RSS.
It is learnt that 45-year-old, Dhana Maya Timsina died on the spot when an unidentified vehicle hit her at Itahari along the East-West Highway.
According to Police inspector Surendra Sitaula, police have been searching the vehicle that hit the woman.
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Three killed in motorcycle accident in Itahari
