The assassination of a Chechen renegade - the first reported political killing in this glitzy city - was masterminded by a close ally of Chechnya's president, Dubai authorities said Sunday, calling on Russia to untie "the knot of this crime." The allegation could have broad implications for President Ramzan Kadyrov, a former rebel now closely allied with the Kremlin and its campaign to quell a 14-year insurrection in Chechnya. One of his bitter foes, Sulim Yamadayev, was gunned down March 28 outside a busy residential complex along Dubai's shoreline. His slaying was the latest assassination targeting Chechen renegades in and outside of Russia. Many observers have linked the killings to Kadyrov, who openly feuded with Yamadayev and his family. Kadyrov has denied involvement.