One policeman was killed and another one was injured as a bomb went off under a police car in the settlement of Shamilkala in Russia's North Caucasian republic of Dagestan, a spokesman for the Russian Investigations Committee's department for Dagestan told Itar-Tass on Thursday. According to the spokesman, the incident took place at about 10:20 a.m. Moscow time on Thursday. The home-made explosive device was planted under the police car. An investigation is underway.