Chief Superintendent Steve Neill says officers would like to hear from people who may have seen anything unusual in Stanley Street at any time in the last few days.
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Held along the city's coastline at Roker and Seaburn, the 28th Airshow has seen a major programme of air, land and sea displays.
A plane carrying David Moyes and the Sunderland AFC squad was force to make an emergency landing due to an engine failure
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