Verulamium Park is currently the scene of a major police incident following reports of a man wielding a knife.
Police were called at 4.41pm following reports of a group of males being seen running through the park and that a knife had been spotted.
Officers were immediately sent to the scene and they carried out an extensive search of the area with support from the National Police Air Service helicopter.
No one suspicious was traced and no one reported as injured. Officers remain in the area.
Anyone with information that could assist enquiries is asked to report information online at herts.police.uk/report or call the non-emergency number 101, quoting ISR 505 of 29 March.
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