Russia's top investigative body says the mayor of a northwestern city has been shot dead in his office by an unidentified assailant. The Investigative Committee says Kirovsk Mayor Ilya Kelmanzon was shot and killed Wednesday. The assailant also killed a local utilities chief who was in Kelmanzon's office, then shot himself dead. The committee wouldn't comment on possible motives, saying an official probe has been launched. Murmansk is Russia's main port on the Barents Sea. The Murmansk region has seen mounting social discontent amid the country's financial crisis. President Dmitry Medvedev dismissed the Murmansk regional governor last Saturday.