A 31-year-old man was charged last night with the murder of seven-year-old Toni-Ann Byfield more than two years ago.
Joel Smith, of no fixed address, has also been charged with the murder of Anthony Pinnock, aged 41 (also known as Tony Byfield and Bertram Byfield), who was believed at the time to have been Toni-Ann's father.
Smith will appear before magistrates in London today but Scotland Yard would not say which court for "operational reasons".
Two men, aged 22 and 30, who were arrested earlier this week in connection with the murders have been bailed to return to north London police stations pending further inquiries.
A 28-year-old woman who was arrested in Merseyside on suspicion of assisting an offender and being concerned with the supply of class A drugs has also been bailed.
Pinnock and Toni-Ann were gunned down in Pinnock's bedsit in Harlesden, London in September 2003.
It was thought he was killed because of a drug debt and Toni-Ann was murdered so that she could not identify the gunman.
At the time of her death, she was in the care of Birmingham social services and had been placed with a foster family in the city.
But when the family went on holiday care workers placed Toni-Ann in London with a girlfriend of Pinnock's.
Following their deaths it subsequently emerged that Pinnock was not in fact Toni-Ann's natural father.