How rarest of rare. Infact the man uses several code to detect door between his building's Kitchen, bathroom or common room (by which they are interlinked). It's now again prove that 4a psycopath "he put his/her complete life to extract his/her best satisfection. Like- India's Manindar Singh Pandher & Surendar Kohli- who murdered & sexually tortured more than 50 kids from very poor family