Kirklees CID are asking a man who came to the aid of a male robbed in an incident near Miln Road in Huddersfield on September 4, 2020, to contact them as part of ongoing enquiries.
The man offered new footwear to the 26-year-old victim who was attacked while walking through a ginnel near Miln Road, police said.
The suspects allegedly restrained the victim and stole his wallet, mobile phone and trainers before making off.
Three males aged 14, 32 and 36 have all been arrested and charged with robbery in relation to the offence.
DC Liam Rye of Kirklees CID, said: “We are continuing to investigate this robbery and as part of our enquiries we would very much like to speak to a man who came to the victim’s aid after the robbery took place.
“This man was kind enough to provide the victim with more footwear after seeing him in a distressed state and we would like to speak with him as a potential witness.
“I would ask him to contact us at Kirklees CID on 101 or make contact with West Yorkshire Police online at www.westyorkshire.police.uk/101livechat "