A gun used in the fatal shooting of a teenager was found by police as they arrested eight people during a raid at an address in south London.
Ryan Bravo, 18, from Brixton, was shot dead in a shop in Walworth, south-east London, last week.
Ashley Bucknor, 19, of no fixed address, appeared before magistrates on Monday charged with murder.
Three other people, two aged 19 and a 17-year-old, have been bailed after being questioned about the murder.
Their arrests followed the raid on the address in Brixton, south London, where eight people - including five 16-year-olds - were held on on suspicion of possessing a firearm and ammunition with intent to endanger life. They were all later bailed.
A 53-year-old woman was arrested at the same address on suspicion of possessing Class B drugs with intent to supply.
Police believe a gun recovered from the address on Brixton's Myatt's Field estate was used in the killing of Mr Bravo, who was shot in the back after going into a Costcutter convenience store with his brother and cousin.
Those arrested at the address were three 16-year-old boys, a 17-year-old boy, a 19-year-old man and a 48-year-old woman, all from south-west London, a 16-year-old boy from south-east London and a 16-year-old boy of no fixed address.
All were bailed until next month.