A seventh suspect has been arrested over the death of a teenager found buried under a garden shed.
Stephen Ojerinola's body was discovered in a makeshift grave some six months after he went missing in April.
His remains, which had been covered with concrete, were unearthed on Sunday.
The 18-year-old's mother, Olayinka, collapsed with grief on Friday as she visited her son's burial spot outside a three-bedroomed semi-detached house in Eltham, south east London.
A post-mortem examination revealed Mr Ojerinola, from Camberwell, south east London, died from stab wounds.
A 31-year-old man has been arrested in south-east London on suspicion of murder and perverting the course of justice. He is being quizzed by officers at a south London police station.
The suspect is the seventh person held in connection with the killing.
Two men - Lee Davies, 35, of Chiswell Square, Greenwich, and William Regan, 36, of Lynsted Gardens, Eltham - were charged with murder earlier this week and remain in custody.
Regan also stands accused of two counts of residential burglary.
Three women, one in her 60s and two in their 40s, along with a man in his 40s, have been arrested on suspicion of murder and conspiracy to pervert the course of justice. They were bailed to return next month.