Agartala, Nov 27 : In a tragic incident, a man mysteriously killed a police officer and four others including his two minor daughters in western Tripura's Khowai District, police said on Saturday. Khowai District Superintendent of police Kiran Kumar K. said that assailant Pradip Deb Roy, 40, shortly after midnight on Friday murdered his two minor daughters - Mandira and Aditi, aged one and seven years and then killed his elder brother Amalesh Deb Roy, 45, when he prevented him from doing so. "When our police team led by inspector Satyajit Mallik reached Ram Chandra Ghat village, Deb Roy attacked Mallik with an iron rod and the police official subsequently succumbed to his injuries in the hospital," the district police chief told IANS. He said that then Deb Roy attacked an auto-rickshaw driver passing through a nearby road and killed Krishna Das, owner of the two-wheeler who along with his family members was returning home from a social function. Deb Roy's wife and Das's son were also seriously injured in the attack and are admitted to a hospital. The police arrested the assailant and started probing into the incident. Police officials said that they have yet to ascertain the motive of Deb Roy, a mason by profession, to kill so many people. "We would also medically examine him whether he has any psychological problem," a police official said. /IANS