Officers want to issue a warning to a group of youths who have been taking part in anti-social behaviour in Gloucester in the past few weeks.
The large group of youths are believed to be boys aged 13 to 16-years-old and have been cycling in and around the city centre in the evenings wearing masks.
In less than a week seven incidents have been reported to Gloucestershire Constabulary where youths were threatening to hit people or run them over with their bikes.
In another incident a boy walked up to an elderly man in the street and poured a can of drink over his head. There is also concerns the same group have been trying to gain access to the old cinema at the Peel Centre.
The group have been described as forty plus in size at times with the majority of them wearing face masks and taking part in intimidating and threatening behaviour.
Officers would urge anyone who has the names of these young adults to contact us. We already have a number of their names and officers will be visiting them and their parents imminently.
Police Constable Rob Bolland said: "This is unacceptable behaviour which we will not tolerate.
"I want to send a message to those involved that we are working hard to get all of your names so it would be wise to stop the threatening and anti-social behaviour now.
"I'd also like to send a message to parents that they should pay an interest in what their children are doing out and about on the streets with the possession of masks."
Anyone who witnesses this type of behaviour or knows those involved should call 101 or email firstname.lastname@example.org and quote incident 176 of 11 October.