The public is being encouraged to report any suspicious activity they may notice around financial institutions, particularly in the run up to Christmas, to notify gardai.
Inspector David Murphy is leading the investigation into yesterday's armed robbery of a post office in Burt.
Two armed and masked men escaped across the border with a sum of cash after threatening staff - no one was physically injured.
The getaway car, a taxi which had earlier been hijacked, was later spotted abandoned at Burnfoot following an appeal on Highland Radio's lunchtime news.
Inspector Kelly also has this advice for business owners: