A 17-year-old boy has been charged in connection with a knifepoint robbery.
At around 3pm on Saturday (July 4), it was reported that two teenagers were threatened with knives near Kings Langley train station.
Cash and a watch was stolen from them.
Following police enquiries, a 17-year-old from London was arrested in Hemel Hempstead on Saturday.
He has since been charged with robbery and has been remanded in custody.
He will appear at St Albans Crown Court in early August.
Police continue to appeal for witnesses and information because investigating officers are trying to trace a second person they believe was involved in the robbery.
Detective Sergeant Darren Machin, from the Three Rivers local crime unit, said: "We do all we can to tackle robbery and knife crime and bring offenders to justice.
"I hope this swift arrest and charge is reassuring to the local community and acts as a deterrent to those involved in, or considering, criminality.
"I would like to thank members of the public for their assistance which led to the arrest.
"We continue to investigate this incident and would like to hear from anyone who witnessed it or has information about it."
Anyone with information can call 101 quoting reference 41/52318/20, visit herts.police.uk/contact or call Crimestoppers anonymously on 0800 555 111.