A man has been arrested in connection with the fatal shooting of a teenager in his bedroom.
Michael Dosunmu, who was 15, was shot at home
Michael Dosunmu, 15, was shot by two gunmen in Diamond Street, Peckham, south-east London, in the early hours of 6 February.
On Wednesday four people were arrested but they have since been bailed to return for further inquires.
Police say the church-going teenager, who had just turned 15, may not have been the intended target.
The latest arrest came after Metropolitan Police Commissioner Sir Ian Blair announced the formation of a temporary taskforce, in addition to Operation Trident, to tackle the spate of shootings in south London.
On Wednesday another 15-year-old was shot dead in his own home in Clapham North, south London.
It was the third fatal shooting of a teenager in south London in less than two weeks.
Michael's older sister was also at home when two gunmen forced their way into the house.
She gave her brother first aid and he was able to say a few words to her, but he died in hospital less than an hour later.
He was a regular at the Celestial Church of Christ, in nearby Bird In Bush Road, and attended Archbishop Michael Ramsey Technology College in Camberwell, south-east London.
Officers from Scotland Yard's Operation Trident team, which investigates gun crime in London's African-Caribbean communities, have not found any link between the boy and local gangs.
Det Supt Gary Richardson, from Trident, said the incident "does not appear to have been a botched burglary" but that the "premises were specifically targeted".
Officers have said they have established a link between Michael's murder and a fatal stabbing that took place near his home on Saturday.
The four people, a man aged 20, and three teenagers aged 15, 16 and 17, have been bailed by police to return in March.