A teacher yesterday allegedly committed suicide falling from fifth floor of a building of Al-fallah Housing Society area of the city. The deceased was  Shamsul Alam, 70, a headmaster of Maheshkhali High School in Cox’s Bazar district. Nizam Uddin, officer-in-charge (OC) of Khulsi police station quoting Shamsul’s family members said that he was mentally unbalanced.