At around 3.30pm on Monday, July 16, an 87-year-old woman was walking along Highfield Road, Doncaster, heading away from the town centre, when a man approached her from behind.
As the man attempted to pull a necklace from around her neck, she fell to the floor, suffering injuries as a result of the fall.
The suspect was unable to grab the necklace after it snapped, and he subsequently ran from the scene towards Kings Road.
Police are appealing to the man pictured to get in touch with them as they believe he could hold '˜vital information' that could assist their investigation.
Anyone else who witnessed the robbery is also asked to contact detectives.
Please call 101 quoting crime reference number 14/104616/18 and ask for information to be passed to DC Hill at Doncaster Police Station.
You can also ring Crimestoppers anonymously on 0800 555 111.