Detectives are appealing for information after a man armed with a knife confronted a group of teenagers.
It is believed the man was looking for money when he confronted the teenagers at a bus stop on Fleet Lane, near Duckeries Park, in Derbyshire Hill, just after 11pm yesterday.
The man, who left empty-handed, was on a bike and wearing dark clothing.
He was described as being aged 30 to 35 and bald.
Detective Sergeant Alan Williams said: “This was a distressing incident for the teenagers and I would appeal to anyone who has any information to come forward so we can find the person responsible.
“An investigation is under way to establish the full circumstances surrounding the incident.”
Anyone with information is asked to contact St Helens CID on 0151 777 6881 or Crimestoppers, anonymously, on 0800 555 111.