Hertfordshire Constabulary closed a Watford road yesterday as armed police, police helicopter and a dog unit searched for a man who reportedly had a knife.
At around 4.45pm yesterday (May 13) police were contacted by the ambulance service following a report for the concern of welfare of a man in Whippendell Road, Watford.
The man was reportedly in possession of a knife, therefore armed officers were sent to the area to support local officers.
Herts Police are treating this as an isolated incident and the man, who has yet to be found, is being treated as a vulnerable missing person.
Enquiries to locate him continue.
Anyone who has any information in relation to the incident is asked to contact Hertfordshire Constabulary via 101, quoting reference ISR 564 of May 13.
Whippendell Road is now open.