Police are investigating after two teenagers were robbed in Limbury Park, Luton, on Saturday, November 3.
At around 3.50pm two teenage boys were walking by the bridge near the river, when they were approached by at least three men, some wearing balaclavas, who demanded they hand over their phones.
The boys were told they would be assaulted if they did not hand over their belongings.
Believing the threat to be very real, the boys handed over their phones, Bluetooth speakers and cash.
The offenders are described as black, and were wearing black tracksuits and black puffa jackets.
Detective Constable Mandy Godfree, investigating, said: “This incident happened in broad daylight and we are keen to speak to anyone who may have witnessed it or seen anything suspicious in the area at the time.
“The park is very popular with dog walkers and we would urge anyone to come forward with information.”
Anyone with information is asked to visit the Bedfordshire Police online reporting centre or call 101 and quote reference number 40/35219/18.