The man shot dead in Shepherd's Bush on Monday has been named as 23-year-ol Randy Osei-Boateng from Leigham Avenue, Streatham.
A post-mortem conducted at Fulham Mortuary on Wednesday found he died from gun shot wounds to the chest.
Both suspects arrested in connection with the killing in Lakeside Road, have now been bailed until June.
A 17-year-old boy was arrested on suspicion of murder late on Monday night and later on a 19-year-old man was held.
A third man was arrested for obstructing police.
They are keeping an open mind about the motive and refused to rule out that the killing was a case of mistaken identity and/or gang-related.
But it is now known the man was shot twice in the chest.
Officers from Trident, which specialises in 'black-on-black' killings, have now set up an incident room in the wake of the killing, which happened at about 4pm on Monday.
According to witnesses, the victim is thought to have been shot as he got into a car. A scooter was later secured and towed away by police.
Appealing for witnesses, Detective Inspector Mark Gower said: "This incident happened at a busy time of day just off the Shepherd's Bush Road and there would have been lots of people in the area at the time.
"There will be people who witnessed what happened and we would urge you to come forward if you have any information.
"Trident understand and suport the communityand will work closely with witnesses who may have concerns about coming forward."
An air ambulance was called to attend the stricken victim, who had to be pronounced dead at the scene.
A spokeswoman for London Ambulance Service confirmed: "We were called just after 4.10pm to reports of a shooting in Lakeside Road, Shepherd's Bush.
"An ambulance, a single response unit and an air ambulance were sent to the scene. One patient was pronounced dead at the scene by the air ambulance doctor."
Witnesses described 'pandemonium' in the area. "There were people running around and then loads of police," said a worker at City News, in nearby Richmond Way. "I saw the ambulances arrive and then the air ambulance.
"Customers have told me they saw the boy getting into his car and then getting shot.
"It is shocking. There are police everywhere."
The whole of Lakeside Road has been cordoned off as forensics officers begin to combe the scene.
Anyone with information should call police on 0300 123 1212.
More as we get it....
DID YOU SEE WHAT HAPPENED? DID YOU KNOW THE VICTIM? ARE YOU AT THE SCENE NOW? SEND YOUR PICTURES AND THOUGHTS TO ADAMCOURTNEY@TRINITYSOUTH.CO.UK
