A man was threatened and robbed of his mobile phone and bag outside Bedford Corn Exchange last night, 30 December.
At around 9.30pm, the victim was approached by four men. They said they were carrying knives and demanded he unlock his phone and hand it over with his bag.
The thieves are described as black and Asian and wearing dark clothing.
Investigating officer Emily Partington said: “This is obviously a very concerning incident and was very traumatic for the victim involved.
“We understand there were a number of people in the area at the time, and would urge anyone who saw the incident or noticed the group of men thought to be involved to contact us.”
Anyone with information is urged to contact Bedfordshire Police on 101 or via Bedfordshire Police’s website, quoting reference 40/47344/18.