He has since worked as a teacher and researcher at the Washington School of Psychiatry, Harvard University, and the John Jay College of Criminal Justice, where he helped to found the Center for the Study of Human Violence.
Setelah itu, ia bekerja sebagai pengajar dan peneliti di Sekolah Psikiatri Washington, Universitas Harvard, dan Kolese Peradilan Kriminal John Jay, tempat ia membantu mendirikan Pusat Studi Kekerasan Manusia.