A Rolex watch worth around £15,000 was stolen from a man as he was walking home from a shop in Barry.
CCTV has been released of a male suspect following an incident near a bus stop close to the rugby club on Merthyr Dyfan Road last month.
Cash was also taken fom the 40 year-old who had been walking home from the Family Shopper store between 7pm and 7.30pm on Friday 28th November.
South Wales Police have described the robbery as "an isolated and unusual incident".
Detective Constable Andy Coakley said: "I would like to reassure the community that we are conducting a thorough investigation. Whilst the CCTV we have sourced is not of the best quality, we believe that somebody who does know the suspect, may recognise him."
The suspect was filmed before the incident running along Morningside Walk from Elizabeth Avenue - atterwards, he was spotted returning up Merthyr Dyfan Road, possibly back onto Morningside Walk.
He is described as tall and slim and was wearing a dark hooded top with a bright white logo on the back, dark jogging bottoms and trainers with a reflective strip around the base.
DC Coakley added: "I believe the suspect would have stood out in the area at this time due to his clothing and demeanour. He was seen on CCTV running to and from where the incident happened."
"We are appealing for anyone with information which might help us identify the suspect and the whereabouts of the stolen watch, estimated to be worth £15,000."
Anyone with information should contact South Wales Police on 101 or via the live web chat, quoting reference no. 2500375490.
Alternatively, you can contact Crimestoppers anonymously on 0800 555 111.

Plans are under consideration to build over 200 houses in a sleepy Welsh village
Sanitary disposal bins introduced in men's public toilets following "Bins for Boys" campaign
Officers called to Dinas Powys Woods after young person enters the river
Vale Council signs off placemaking plan for Barry
Plans filed to use Blackweir Fields for a series of live events this summer
Plans filled for controversial housing development in Cowbridge
Cardiff Council pledges to work with new Welsh Government to tackle trouble-plagued hospital
RNLI issues Sully Island safety advice after first call out of the year to the Island
Morio Lounge on course to open at Nell's Point in May
Vale Council appoints specialist contractors to carry out road improvements
Three men jailed for their roles running a drugs line which supplied cocaine in Barry
Police appeal for witnesses after fatal Penarth Road collision
New Beach and country park facilities opened following major investement
RNLI centre at Barry Island welcomes lifeguards back to Whitmore Bay
Severn tidal lagoons progress