Original sentence: American historian Norman Naimark writes:  The deportation was justified by the materials prepared by NKVD officer Bogdan Kobulov accusing Chechens and Ingush in a mass conspiracy preparing rebellion and providing assistance to the German forces
Edited sentence: American historian Norman Naimark writes:  The deportation was supposedly justified by the materials prepared by notorious NKVD officer Bogdan Kobulov accusing Chechens and Ingush in a mass conspiracy preparing rebellion and providing assistance to the German forces