The National Investigation Agency (NIA) on Friday questioned IIT-Guwahati professor Arupjyoti Saikia for the fourth time in a week in connection with the violence during the protests against the Citizenship Amendment Act in Guwahati last month.
Arupjyoti Saikia, a professor of History, was summoned to the NIA office in Sonapur, on the outskirts of Guwahati.
"Arupjyoti Saikia was questioned for several hours. He is being questioned as a witness to Akhil Gogoi's case," his advocate Santanu Borthakur told news agency PTI.
Arupjyoti Saikia was first questioned on February 1 in a case related to alleged "terror activity" by farmers' rights activist Akhil Gogoi.
Akhil Gogoi was arrested on December 12 as a "preventive measure" in view of the deteriorating law and order situation in the state and his colleagues were taken into custody the next day.
However, the Assam Police registered an FIR on December 13. The case was abruptly handed over to the NIA the next day.