Ray was waylaid at Borpora area and beaten up with wooden and bamboo sticks injuring him on his head and eyes, the sources said.
The student leader, demanding a separate Kamatapur state dividing Assam and Bengal on '50/50' basis, was travelling alone in his car when the incident took place, they said.
He was admitted to a private hospital for medical treatment.
Police suspected it to be an attack by the rival AKRASU Hiteswar Barman faction supporters for Ray's meeting with Bodo territorial Council (BTC) leaders headed by Hagrama Mohilary, yesterday, deciding to raise their demands together and share policy and strategies on their individual movements for separate states.