Mohammed Farah, 19, from Birmingham, died from a single gunshot wound to the head shortly after 10pm on Thursday night, in Milton Keynes.
The incident happened near an off-licence on Fishermead Boulevard, on the Fishermead estate, not far from the city centre.
His 18-year-old friend, Amin Ahmed Ismail, from London, was also shot in the head but was taken to hospital where surgeons operated on him and placed him on a life support machine.
He died yesterday while under armed guard.
Police said Amin had been found slumped over Mohammed's lifeless body after a member of the public reported the sound of three gun shots
They are working to establish the type of gun used to kill the teenagers but believe both shots were fired from the same gun by one gunman.

The pair were known to police but they said the incident "seems to be completely out of proportion to the criminality they were involved in".
A large area around a terraced house was yesterday cordoned off while they carried out an investigation.
A large blue tent covered the spot where Mohammed died and a forensic team in boiler suits examined the area.
His uncle, Rashid Hirad, said that his nephew had been in hiding for the last few weeks.
He said that he had been beaten up repeatedly and his mother had moved to Birmingham in an attempt to avoid the trouble but he kept returning to Milton Keynes to visit friends.
Rashid said: "She decided to move from Milton Keynes to Birmingham because she wanted to run away from these people but she couldn't, all the time he is coming back to Milton Keynes to visit friends and at last it happened."
 

Mohammed was born in Norway to Somalian parents. He had three brothers and a sister and had been living with his mother Fadumo Ahmed in Birmingham where he was going to attend a college access course so that he could apply to university to do business.
Another uncle, accountant Sharmaarke Mohammed, 38, said: "When I heard he had been killed I thought he must have been visiting his father in Somalia - which is a war-torn country - not Milton Keynes which we thought was peaceful.
"He was a well-behaved and likeable with a lot of friends. As far as I know he had not been in any trouble with the police.  

 
"There are two stories about what happened. One is that he was the victim of a drive by shooting, but as the gun was fired at the two of them I don't think that is likely. I think it is more likely that he and his friend had been chased up the alleyway and the gunman was waiting for them."

Sharmaarke said he did not know the name of the other boy who was shot, saying that he was a friend of his nephew who lived in London.
Members of the 10,000-strong Somali community in Milton Keynes gathered at the murder scene to pay their respects. Women in colourful head scarves were wailing in grief.
Neighbours speculated on a motive for the killings.
One white woman, who did not want to be named, said: "It could be drugs, could be gangs or could be race related.
"In the past there has been trouble between white youths and some of the Somalis. You would often get groups of 50 or so Somali young boys sitting out of the grass here together. It is a funny area there are groups of Somalis, groups of people from Eritrea and there are groups of Poles."
Detective Superintendent Rob Mason, who is leading the investigation, said: "We are obviously still at a very early stage of this investigation.
"We believe that the victims in this incident are friends, but we do not know if the offender is known to them.
"I realise that there is a lot of concern in the community as well as a lot of speculation about the reasons behind this incident. We are still trying to establish the facts and cannot be drawn on rumours and speculation.
"We have a large and highly visible police presence in the area which should provide some reassurance to the community at this difficult time."
He urged anyone with information on the shootings to contact the Thames Valley Police.
Isabella Fraser, 75, a Lib Dem ward councillor and Chair of the local Equality council said: "It is a great shame. We have been working hard to integrate the communities.
"The trouble is we have transitory populations and people do not have roots in the community. Many people have not lived here long. There are a large number of Somalians here, East Europeans and Ghanians and Kenyans.
"I have seen the mother of the 19-year-old boy this morning and she is devastated."