KUALA LUMPUR: The Prisons Department is fully responsible for the security arrangements for former Prime Minister Datuk Seri Najib Tun Razak, who has been serving the remainder of his jail sentence under house arrest at his residence in Langgak Duta here since Tuesday (Nov 10). Inspector-General of Police Tan Sri Mohd Khalid Ismail said the police, as a law enforcement agency, maintained close cooperation with the Prisons Department to ensure compliance with.