They particularly want to hear from motorists confronted by one of the suspects who attempted to get into people’s cars and wave down vehicles in the Porthill area of the town.
The two thieves fled with the ring from Goldsmiths Jewellers in The Square shortly after 3.30pm on Tuesday pursued by a member of the public.
Both men ran along the back of Rackhams into College Hill, Swan Hill into Cross Street and then onto St John’s Hill where they split up near the junction with Murivance.
One man made his escape running down Town Walls while the other ran into the Quarry and across Porthill footbridge still pursued by the member of the public.
Police Constable Lee Saunders, the investigating officer, said:
“At this point, the suspect jumped into a black VW Polo car which was pulling up outside the Boathouse pub. He shouted at the driver to drive off but the occupants refused and he eventually got out.
“He then ran into the road and attempted to stop a Royal Mail van which drove around him and then tried to stop the next vehicle, a large truck, which again drove round him.
“The suspect then ran to a dark coloured saloon parked in the pub car park driven by a woman who was on her mobile phone. He attempted to open her passenger door before running across the road into Park Avenue, onto Pengwern Road before entering several back gardens.
“The man pursuing him had kept him in sight and police officers directed to the area, quickly arrested the suspect.”
PC Saunders urged anyone who might have seen the man at any point during the pursuit, or at the jewellers beforehand, to contact Shrewsbury police station on 101.
“We particularly want to speak to any of the drivers he attempted to wave down or whose cars he tried to get into. Do get in touch as a matter or urgency.”
During the theft, one man entered the shop and asked to look at a gold diamond ring. He placed it on his finger while the second man, who remained outside, pushed the shop door open for his accomplice to run out.
The man arrested is described as being of mixed race, in his twenties, about 5ft 10ins tall and of stocky build. He was wearing a light grey hooded top and matching tracksuit bottoms and initially, a black baseball cap, which was later discarded.
The man who made his escape down Town Walls is described as white, around 6ft tall, of medium build, in his late twenties with facial hair. He was wearing a badly fitting two tone grey jacket and a royal blue woollen hat with a white pattern.
A 21-year-old man from Liverpool was taken into custody and later given police bail with conditions while inquiries continue.
The ring has not been recovered.
Shropshire Live is regulated by