Robbers are believed to have carried imitation guns while forcing staff to hand over cash in a raid on a betting shop in Luton last Sunday.
The robbery took place at Ladbrokes in Chapel Street at around 9.45pm on October 25, when two men walked into the store demanding cash.
Both men were described as black with their faces covered by bandanas. They tried to climb over the counter before a staff member handed over money from the tills.
The men were also thought to be carrying imitation guns and made off in the direction of Matalan.
One of the men wore a grey tracksuit, while the other had a navy tracksuit.
Det Sgt Tom Stean, investigating, said: “This was understandably a distressing incident for the shop workers involved but thankfully no-one was hurt and we do not believe any viable weapons were used in the attack.
“I would urge anyone who has any information about yesterday’s frightening attack to contact me on 101.”
Bedfordshire Police advise never to take matters in your own hands during a robbery. If a crime is in progress, always contact police on 999 immediately.
Anyone with information call DS Stean on 101, or Crimestoppers anonymously on 0800 555 111.