A man was sprayed with an "unknown substance" during a car theft at a petrol station.
Police are now investigating the robbery on Sunday August 8 at the petrol station in Edinburgh Way, Harlow.
Officers are also urging witnesses to come forward.
An Essex Police spokesman said: "We are investigating a robbery in which a man’s car was stolen. We were called at 2.30am on Sunday 8 August after the 28-year-old victim reported he had been sprayed in the face with an unknown substance outside a petrol station in Edinburgh Way, Harlow, and threatened.
"His blue Vauxhall Astra was stolen. The victim was not seriously injured and our enquiries remain ongoing.
"Witnesses and anyone with information are asked to contact Harlow CID quoting reference 42/161587/21."
Alternatively see www.essex.police.uk, call 101 or contact Crimestoppers 100% anonymously on 0800 555 111.
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