A Police official was killed on Monday in Makhachkala, the capital of Russia\'s North Caucasus republic of Dagestan, the Russian Interior Ministry said. Lt. Col. Valery Aidayev, head of the district Criminal Investigation Department, was shot dead by an unidentified assailant, Russia\'s News Agency (RIA Novosti) reported. Police have mounted a citywide manhunt for the assailants but no suspects have been detained yet. The Islamist insurgency, once confined largely to Chechnya, has spread in recent years across the North Caucasus. Attacks on security forces, police and civilians are also reported regularly in the neighboring republics of Ingushetia, Dagestan and Kabardino-Balkaria.