A man believed to be aged 18-years-old has died of a gunshot wound to the head.
Emergency services were called to St Ann’s, Barking after reports of a shooting at 7pm on Sunday.
The man was taken to an east London hospital where he was pronounced dead at 10.25pm.
Next of kin have been informed but formal identification and a post-mortem examination has not been completed.
A 20-year-old man has been arrested in connection with the murder and is currently in custody at an east London police station.
Anyone who witnessed the incident or has any information is asked to contact detectives on 101 or call Crimestoppers anonymously on 0800 555 111.