In a televised appeal to help find his killers, Michael Dosunmu's sister Shakira said she fought to keep him alive by giving mouth-to-mouth resuscitation.
''I did CPR (cardio pulmonary resuscitation) for him,'' she told the BBC's Crimewatch. ''I did it for the 15 times I put air in his mouth -- nothing. I did it again. I was just screaming.
''I said 'Michael you can't leave me like this. Michael, Michael, Michael, wake up, wake up' -- but he didn't respond.'' The teenager was killed when two intruders burst into his house in Peckham, south London, on February. 6 in what police said may have been a case of mistaken identity.
He was the third teenager to be shot dead in south London in less than two weeks. Extra armed police were deployed as part of a crackdown on gun crime.
The boy's father, Rasak, said his wife was in Nigeria when their son was shot.
''I was so worried about how my wife would take the killing of Michael,'' he said. ''So I phoned and said that Michael was seriously sick and she needed to come back.
''What goes around will turn around one day. It might be Michael today. It might be their own family tomorrow.'' The teenager's mother, also called Shakira, said: ''I don't think there is any other pain that is more painful than this. It's feelings that can never go away.'' The Crimewatch appeal goes out today.
REUTERS PDM PM1539