LONDON — Boris Berezovsky, the exiled Russian oligarch and long-time opponent of the Kremlin, died at his home in Britain on Saturday aged 67 in unexplained circumstances, officials said. British police launched a full investigation into the death at the mansion in the well-heeled commuter town of Ascot, near London, saying it was "currently being treated as unexplained". Berezovsky's lawyer Alexander Dobrovinsky told Russian television the tycoon had committed suicide after suffering from weeks of depression over his huge debts, although another friend strongly denied this. Berezovsky was one of handful of businessmen who made a fortune out of the...