A man was stabbed with a machete in his upper back after a group of men approached his car window in Slough.
The man in his late teens was a passenger in a black Vauxhall Corsa waiting at the traffic lights on London Road at the junction with Blandford Road South, when three men approached the car.
The assault took place between 10pm and 10.15pm on Friday (August 26) as one of the attackers smashed the car window before stabbing the victim.
The car then drove away with the man receiving treatment at Wexham Park Hospital for a large cut to his upper back.
He has since been discharged.
The attackers are described as black males, around 5ft 9ins tall, of skinny build, wearing balaclavas over their faces and dark clothing with the hoods up.
Detective Constable Oliver Elston, of Slough CID, said: “I am appealing for any witnesses to this incident to please come forward.
“Also, if you have any CCTV footage in the area or any dash-cam footage if you were driving in the area around the time, I’d also ask that you check any recordings in case it has captured something that could assist our investigation.