The most recent incident took place at about 10.35am yesterday, Sunday April 8. A man entered a store on Gunthorpe Road, Peterborough with his face covered and carrying a metal baton.
He demanded money but left with just cigarettes. Nobody was injured.
Anyone with information is asked to call police on 101 quoting reference CF0183800418.
It follows five previous similar incidents at shops in the city. Police are keeping an open mind as to whether they are linked.
One of the places targeted was Ladbrokes at the Werrington Centre in Skaters Way. More than £1,000 was stolen across two robberies and staff threatened with weapons which police said are not believed to be firearms.
The first incident took place at about 9.30pm on Wednesday, March 28 and the second on Monday April 2 at about 5.15pm.
On both occasions a man entered the bookmakers, threatened staff and demanded money.
As well as taking money, a tablet computer was also stolen during the second robbery.
The man in the first incident is described as white, aged 21-40 and 5’11” to 6’. He was wearing a green jacket and a dark coloured beanie.
The man involved in the second incident is described as white, but with a tan, 5’9”, stocky build with stubble and aged approximately 30. He was wearing a black hoodie, jeans and a beanie hat.
Anyone with information regarding these incidents should contact police, quoting CF0165590318.
The One Stop in the Parnwell Centre was also robbed before 7.45am last Wednesday morning, April 4.
A man with his face covered entered the shop and is believed to have made off with some cash,
Police are also investigating a robbery at the same premises on Friday March 30 at about 7.45am. Two men entered the shop and one went behind the till and took a handful or tobacco packs.
When challenged the man pulled out a knife. No one was injured.
Anyone with information should contact police quoting CF0167870318.
Shortly before the robbery at the One Stop last Wednesday, two masked men assaulted a member of the public at Bal’s General Store, leading to officers cordoning off a stretch of St John’s Street.
Police were called about the incident at 7.25am.
A spokeswoman said two masked men entered the store and demanded money before assaulting a member of the public.
They left empty handed.
Anyone with information on that attempted robbery should contact police quoting reference CF0167870318.