The Court of Appeal in Belfast has ordered that Brian Shivers face a retrial for the murders of two British soldiers at Massereene barracks in 2009.
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A large tent has been put up around the area while investigations continue.
The kind gesture touched the hearts of many who shared and retweeted words of support for the officer on Twitter.
Two workers were forced into a back office as the robbers tried to force their way into a safe, police say.