Mrs Bates co-owned Time Centre

Marian Bates, 64, died in hospital after being shot in the chest during a raid at the Time Centre, in Arnold, Nottinghamshire.

Police said the thieves, who were in their late teens or early 20s, were confronted as they dashed from the busy shopping area on a stolen blue Gilera Runner scooter.

An Asian van driver, who had been parked close to the shop, ran into the road and attempted to stop one of the thieves.

A pedestrian later tugged at one of the attackers as they drove past.

Police closed off Front Street

A police spokeswoman said: "Officers particularly want to hear from an Asian man who was sitting in a white Transit-style van in Front Street.

"Witnesses say that he appeared to confront one of the offenders as they were leaving the shop, and he may have vital information.

"Another witness is a man in Market Square, who it is suggested tried to pull the offenders off the moped as they sped away.

Car collision

"Witnesses said he tugged at one of them but was shrugged off."

Detectives said that the scooter, which had been stolen a month ago in Nottingham, may also have been involved in a collision with a red Nissan type car before it was dumped at the rear of an Indian takeaway in Rolleston Drive.

Mrs Bates' husband Victor, 64, and one of the couple's daughters Xanthe, 34, who were both in the store at the time of the attack, have been released from hospital after receiving treatment for head and facial injuries.

Police said they were being cared for by family and friends and would be interviewed later.