A man suspected of murdering a key witness in torture accusations against the president of Chechnya has been arrested.The suspect, a Russian man of Chechen origin, was seized by Polish police at a hotel near Warsaw. He was the subject of an international arrest warrant. Austrian authorities believe he was involved in the fatal shooting of Umar Israilov in a Vienna street last month. Israilov was a former bodyguard of the pro-Russian Chechen president Ramzan Kadyrov. Israilov fled to Austria where he filed a complaint against Kadyrov, accusing him of torture and other human rights abuses in Chechnya. Prosecutors in Vienna are to release results of their investigation into Kadyrov within the next few weeks.