A group of young men allegedly threatened a boy while they were wearing "animal and ghost masks" in a Northampton park.
Police are appealing for witnesses after receiving reports of a group of young people acting suspiciously in Victoria Park and near Spencer Bridge Road.
"A group of about four young men, all reportedly wearing animal and ghost masks approached and allegedly threatened a young boy at about 6.25pm on Sunday, June 8," said a Northamptonshire Police spokeswoman.
"The incident took place between Dallington Brook and the basketball court near to Spencer Bridge Road."
Officers would like to speak to anyone who may have witnessed this incident or who may have seen a group of people wearing face masks in the park.
Witnesses or anyone with information can call police on 101 or Crimestoppers anonymously on 0800 555 111.