The grieving sister of a churchgoing teenager who was shot dead in his bed has spoken of her desperate attempts to save his life.

Michael Dosunmu, 15, was murdered, in what police believe was a case of mistaken identity, by two gunmen who burst into his home in Peckham one night last month.

His sister Shakira said that as he lay dying, “I did CPR [cardio-pulmonary resuscitation] for him, 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.”

Her brother, who was so determined to become an architect that he was being home-tutored in mathematics and science, was one of three teenagers shot dead in a spate of gun violence in South London in 12 days last month. He was murdered two days after his 15th birthday.

BBC One is to broadcast an interview with his parents and sister on Crimewatch tonight in the hope that it will encourage those with information about the identity of the murderers to contact the police.

Michael’s mother, who is also called Shakira, said that the family would have to learn to live with the grief of losing him, but it would never disappear.

Mrs Dosunmu, a nurse, said: “It is terrible. I don’t think there is any other pain that it is more painful than this because if I reflect back on Michael — it’s horrible. It’s so sad that his life has been taken away and it’s feelings that can never go away and we will just have to learn to cope with it.”

Michael’s father, Rasak, a senior psychiatric nurse, explained that his wife had been visiting Nigeria when their son was murdered. He said: “I was so worried about how my wife would take the killing of Michael. So I phoned and said that Michael was seriously sick and she needed to come back.”

It was only when she returned to London that Mr Dosunmu told his wife that their son was dead.

Mr Dosunmu warned those withholding information about the killers that other boys were in danger of being murdered in the same way: “What goes around will turn around one day. It might be Michael today. It might be their own family tomorrow.”

The shooting, on February 6, was the second in a series of South London murders that exposed the area’s brutal culture of guns, gangs and drugs.

Michael was in his bedroom in the early morning when gunmen burst in and opened fire. Police believe his killers got the wrong person, and have linked the murder to the death of Javarie Crighton, 21, who was stabbed two days earlier in a nearby street.

Michael died a few hours later in King’s College Hospital.

Six people have been arrested and bailed in connection with Michael’s murder.

The gun violence has continued in Peckham. Early yesterday a policeman was shot there; he was wearing body armour and was not injured.

Michael was the second of three schoolboys to have been shot dead in 12 days. James Andre Smartt-Ford, 16, of New Malden, died after he was shot at least twice in front of hundreds of people during a disco at Streatham Ice Arena. Michael was shot three days later. A few days after that, Billy Cox, 15, was shot dead at his home in Clapham.

Figures released under the Freedom of Information Act have disclosed that children as young as ten have appeared in court on gun charges. Since April 2005, in cases investigated by Operation Trident, Scotland Yard’s black-on-black gun crime unit, 16 teenagers have been charged with murder, including one aged 14.

Measures proposed last month include membership of a street gang being an “aggravating” factor when young offenders are sentenced. There have also been moves to ensure that those under the age of 21 caught with a gun are given a five-year custodial sentence.

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