West Midlands Police have released a CCTV image of four men they would like to speak to.
A 64-year-old man was forced to hand over £20 to a robber to retrieve his phone moments after he was threatened at knifepoint.
West Midlands Police said the 64-year-old was waiting for public transport at Dudley bus station when he was targeted at around 12.30am on Sunday, January 5.
One man threatened him with a blade and grabbed the phone off him
But the victim managed to get his phone back after handing over £20, a spokesman for the force revealed.
CCTV images of four men police would like to speak to has since been released.
An online appeal reads: “Do you recognise any of these four men?
“We’re investigating a robbery at Dudley bus station at 12.30am on Sunday, January 5, while a 64-year-old man was waiting for a bus.
“Four men approached him, produced a knife and grabbed his phone off him. He managed to get his phone back, but only after handing over £20, before they escaped.
“Anyone with information can contact us via Live Chat at west-midlands.police.uk between 8am and midnight or call 101 anytime.
“Crimestoppers can be contacted anonymously on 0800 555 111. Please quote crime reference 20DY/4595N/20.”