Police say a gas canister was used to blow up a cash machine during an overnight raid last week.
Burglars rammed the front of the Co-op store in Cunningham Way, Leavesden, shortly after 2am last Thursday.
They left a trail of destruction, smashing the window of the store, knocking down a bollard, as well as causing significant damage to the ATM machine.
They were able to steal a "considerable" amount of cash before three people were seen fleeing the area in a white Mercedes.
A police cordon was in place throughout Thursday morning. The fire service also attended to check the safety of the building - which was deemed fine.
Detective Sergeant Steven Boddy from the Rickmansworth local crime unit who is investigating the incident are appealing for witnesses and information said: “This was a well-executed theft and we need to trace those responsible as a matter of urgency. The incident itself was very noisy and anyone nearby would have been aware."
Any witnesses or anyone with information should contact DS Boddy on steven.boddy@herts.pnn.police.uk or 101, quoting reference ISR 043 of 13/06/2019 or contact Crimestoppers anonymously on 0800555111.
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