 During the Korean War, he investigated conditions in Korean prisoner-of-war camps for George Washington University's Human Resources Research Office.From 1947 to 1953, Ohlin was a sociologist for the Illinois Parole and Pardon Board where he was responsible for interviewing prospective parolees and making recommendations to the board for their consideration.He directed the Center for Education and Research in Corrections at the University of Chicago from 1953 to 1956.