A group of friends were threatened with a knife before thieves stole a boy’s bike in two different robberies on the same evening.

Hertfordshire Constabulary is investigating the two incidents in and around Cassiobury Park, Watford, both of which occurred on Tuesday, June 2.

In the first incident, two 15-year-old boys were leaving Cassiobury Park with several friends at 8.30pm when they were called over by two men sitting on a fence.

Police say the men, aged in their late teens to early twenties, tried to talk to the group before demanding their AirPod earphones.

One of the victims handed his earphones over but when another refused, a suspect threatened the group with a knife, police said.

The second victim was chased by the suspects down Gade Avenue after running off, but he managed to get away.

Both suspects were around 6ft tall, and police described one as being mixed race with curly afro hair. He wore a navy tracksuit.

The other was described as having tanned or olive skin and black hair in a buzz cut style. He wore jeans and a green bomber jacket.

In the second incident at 9pm, a 13-year-old boy was pulled off his bike by a group of men as he was cycling past the Horns Pub in Hempstead Road.

One of the men threatened the victim and ordered him to hand over his bag, phone and bike before they left the area.

The victim was not injured.

No arrests have been made.

Police are now appealing for information and witnesses following the two incidents.

Watford Chief Inspector Matt Phillips said: “We understand that news of these incidents will be unsettling for the community but I want to reassure residents that we are supporting the victims and have launched an investigation into each incident.

“I have already increased both our high-visibility and plain-clothes patrols around the area of Cassiobury Park, and detectives in the Local Crime Unit are continuing to carry out extensive enquiries.

“We believe either a Volkswagen or Vauxhall Corsa was in the area at the time of the offences. Did you see a car matching the description in the area?

“Were you in the park at the time of the incidents? Did you see any suspicious activity? It was a pleasant evening and we believe many people would have been out enjoying the sunshine.

“If you have any information at all, however insignificant it may seem, we would like to hear from you.”

The crime reference for the first incident is 41/43052/20 and the second is 41/43023/20.

Anyone with information can email investigating officer DC George Lewin at george.lewin@herts.pnn.police.uk or call 101.