The owner of a family-run jewellers was threatened with a stun gun during a daytime robbery.
The crook – wearing sunglasses, a hat and scarf to cover his face – struck at Daisy Chain Jewellers in St John’s Road, Boxmoor, at around 9.20am on Tuesday.
He placed a handwritten note on the counter threatening the owner and then went into a back room and grabbed items of jewellery before making off.
He was chased by a nearby shop worker but got away and was seen darting down alleyways before getting on a silver bike and making off.
Det Con Jane Swift said: “We believe that there are a number of people who have not yet spoken to police who may have given chase. I would ask that these people and any other witnesses get in touch as they may have information vital to our investigation.”
Contact police via the non-emergency number 101 quoting crime reference D1/13/2151.