BRATISLAVA (Reuters) - A Slovak mafia boss was shot dead this week in what police believe to be the latest in a series of gangland killings. Milan Holáň, 35, described by police as the mafia boss for northern Slovakia and his 23-year-old companion, a former member of army Stanislav Vnuk, were gunned down in a hotel bar in the northern town of Žilina, a newspaper said. Both men were killed immediately, by more then 10 bullets. The assailants escaped by car, the paper quoted police sources as saying. The murder of Holáň is the latest in a growing number of violent attacks. In September, Róbert Holub, 27, linked by police to the eastern Slovak underworld, was machine-gunned to death in a Bratislava hospital. He had been seriously wounded a few days earlier in an assassination attempt. Police statistics show 111 murders were committed in Slovakia during the first nine months of this year, of which 67 have so far been solved. Many of the unsolved murders are linked by police to the underworld.