A masked hooded man entered a shop and tried to rob money from the till while warning staff he was armed with acid.
Detectives are hunting for the offender who entered the McColl's convenience store in Birchwood, Warrington, and demanded cash.
The incident happened at about 8.40pm last Sunday on Admirals Road in the town.
It is believed he was in possession of a knife and a canister he claimed contained acid.
The man attempted to enter the till area but was stopped by a staff member.
He fled the scene empty-handed.
In the melee, a shop workers sustained minor injuries to his hand.
The offender is white, around 5’7” to 5’10” and of average build.
He was wearing a black face mask, a dark hoodie, dark trousers and light coloured trainers.
Officers are now urging anyone with information about the incident to get in touch.
Detective Constable Jill Peggs, of Cheshire Police, said: “This incident has not only left the member of staff with slight injuries but also incredibly shaken.
“We are doing all we can to find the offender responsible and bring him to justice while a number of enquiries are ongoing.
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“I would urge anyone who may have seen anything around the time of the incident to get in touch.
“Also I would like to ask anyone who may have captured dashcam or CCTV footage of the suspect to call Cheshire Police on 101.”
Anyone with information is urged to call Cheshire Police on 101 quoting IML 804376 or report it via https://www.cheshire.police.uk/ro/report
Information can be passed on to Crimestoppers anonymously by calling 0800 555 111 or report it via https://crimestoppers-uk.org/give-information/forms/give-information-anonymously.
