Part of a town centre was closed off for more than an hour after a mystery white powder was scattered in a number of locations.
Police and firefighters cordoned off an area of the Tuesday Market Place in King's Lynn shortly after 3pm.
Analysis revealed the suspicious substance was corn starch flour and posed no threat to the public.
Officers were called around 2pm following reports a male had been seen scattering a white powdery substance from a plastic carrier bag in a number of places around the town including South Quay and Tuesday Market Place.
Emergency services attended the scene, including hazardous materials (HAZMAT) specialists from the Norfolk Fire and Rescue Service.
Officers would like to speak to a man and woman in connection with this incident. The man is described as being white, aged in his 40-50s, with short hair, wearing a parka jacket and was riding a push bike. The woman is described as having long hair and wearing a red top.
Witnesses or anyone with information regarding this incident should contact Norfolk Police on 101 or alternatively call Crimestoppers anonymously on 0800 555 111.
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