A supermarket staff member was threatened with a knife during an aggravated burglary in Bushey Heath.
Police have launched an investigation after three break-ins in Hertsmere which officers are linking.
One was at Budgens in High Road, which involved a balaclava-clad suspect with a knife threatening the staff member before taking a large amount of cigarettes and cash. A hammer was also left at the scene.
It happened between 8.45pm and 9.45pm on Sunday, March 26, with the suspect described as dressed all in black and wearing trainers, trousers, a jacket, balaclava and gloves.
Police urged anyone with information to report it via 101, using crime reference number 41/24792/23.
Two similar aggravated burglaries happened at Tesco Express in Andrew Close, Shenley, and Studio Way Food and Wine in Borehamwood, on March 7 and 13 respectively.
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DC Mollie Goodwin, who is investigating, said: “Our enquiries are continuing, and we are appealing for any witnesses to please come forward.
“We believe these three incidents are linked, and we would like to hear from anyone who may have information or saw anyone acting suspiciously around this time.”
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