Officers visited a Welwyn Garden City pub in the early hours of Sunday morning after a man was seen with a knife.
Police were called to The Hedgehog in Shoplands, following reports of a man with a knife in the pub garden.
Officers attended the scene and carried out a search, but no suspect was traced.
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The Hedgehog has been shut since the weekend, with a notice on the door confirming they were closed "until further notice due to a serious incident".
But the Welwyn Hatfield Times understands this has now been change to just read "closed until further notice".
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Herts police confirmed the pub was cleared during the incident, but the did not ask or request for the pub to remain closed.
This newspaper has tried to contact The Hedgehog, but has yet to receive a response.
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