The problem with categorising Mijailovic is that he was "a threshold case", Sten Levander, a forensic psychiatry professor from Malmo University Hospital, told BBC News Online.

BBC: NEWS | Europe | Doctors split over mind of a killer

Dr. Welner is Associate Professor of Psychiatry at NYU School of Medicine and Chairman, The Forensic Panel.

CENTERFORSECURITYPOLICY: Hasan was not a ��sleeper,�� says forensic psychiatrist