A teenage boy was rushed to hospital after he was hit over the head with a laughing gas canister.
Police were called to Leyton High Road shortly at around on May 12 after a 17-year-old boy was the victim of an unprovoked attack.
The teenager had been walking along the street when he was approached by a man who struck him over the head with a nitrous oxide canister.
He was rushed to hospital by the London Ambulance Service where he received treatment for a head injury before being discharged.
Officers believe that the suspect was a passenger in a car that pulled up alongside the victim before the attack.
Police have now released CCTV footage of a man they would like the public to identify.
Detective Constable Alexandra Varga, from the local policing team in north-east London, said: "This was an unprovoked attack on a young man who was walking home and we are determined to catch the person responsible.
"We have carried out extensive CCTV enquiries and have found footage of the suspect leaving the area after the attack.
“Whilst I acknowledge the image of the suspect is not clear, I'm hoping somebody will recognise him from the footage we have released."
Anyone who can help the investigation is asked to call 101 quoting reference 17/12May.
To remain anonymous contact the independent charity Crimestoppers on 0800 555 111.
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