Detectives investigating an attempted robbery in Hemel Hempstead are appealing for witnesses and information.
The incident occurred between 6.20pm and 6.35pm on Monday, July 10.
The victims, two boys aged 13, were approached in St Albans Road by two older teenage boys who made threats of violence and tried to steal their bicycles.
The victims were then chased to Nandos in Jarmans Park where an unknown family intervened and the offenders left the area.
Both suspects are described as white, aged around 15 to 16 years old and spoke with Irish accents. One was riding a bicycle.
Detective Constable Laurence Harwood said: “The victims were not hurt during the incident but are understandably upset about what has happened.
“I am keen to trace the family who assisted them and would ask that they please get in touch. I would also like to hear from anyone else who may have witnessed the incident, as there would have been a lot of people in the area at the time.”
Anyone with information is asked to contact the Hemel Local Crime Unit on the non-emergency number 101, quoting crime reference D1/17/5537 or D1/17/5539.