Deputy Assistant Commissioner Martin Hewitt, of the Metropolitan Police, says there remains "gaps in understanding" regarding the death of MI6 worker Gareth Williams.
But he has concluded, following two years of investigation, that it is "most probable" that the codebreaker was alone at the time of his death.
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Experts say a trial into an early Ebola vaccine shows it is safe, but did not perform as well as had been hoped.
Frequent snowfall expected across much of the north this evening and strong northeasterly winds will make it feel noticeably cooler.
A Jewish leader was forced to escape from the camp through a window last night, when he was locked in during a TV broadcast.