The National Investigation Agency (NIA) has summoned Indian Institute of Technology (IIT), Guwahati professor Arupjyoti Saikia.
Sources said the central investigating agency on Saturday issued summon to Saikia as a witness in an unspecified case.
According to sources the case is relating to protests against the Citizenship (Amendment) Act (CAA) in Assam.
Saikia was questioned for several hours in NIA office at Sonapur on the outskirts of Guwahati and asked about his telephone calls to Krishak Mukti Sangram Samiti (KMSS) activists during anti-CAA protests.
Earlier, Assam finance minister Himanta Biswa Sarma had in a press meet indicated that a person working in a central government organisation was directly involved in the violent anti-CAA protests in Guwahati.
Without naming anybody Sarma had stated that there was electronic evidence that a leading academician from Assam was trying to orchestrate the burning of Assam Secretariat at Dispur capital complex.
Saikia is a professor of History in the Department of Humanities and Social Sciences at IIT-Guwahati. Among his books is The Unquiet River: A Biography of the Brahmaputra.
The NIA has so far arrested four KMSS leaders—Akhil Gogoi, Dharya Konwar, Bitu Sonowal and Manash Konwar for their alleged links with Maoists.
The NIA has also interrogated another KMSS activist Hussain Mohammad Sahjahan.