Police were called to Victoria Road, Feltham at about 17:00 GMT on 12 January following reports of a stabbing.
Maliki Sharma, 18, was taken to hospital where he was later pronounced dead.
Det Ch Insp Allam Bhangoo, who is leading this investigation, said: “My thoughts remain with Maliki’s friends and family during this unimaginably difficult time.
“We understand that this incident has been distressing for the local community and residents can expect to see an increased police presence over the coming days.”