Police were called to reports of an argument in Saint George's Road and found Suhayb Abdulkadi, 24, with stab wounds.
Kol Page died in 2024 after suffering escalating violence while in the couple's care, a court heard.
The 15-year-old was charged with the murder of Eghosa Ogbebor who was fatally shot in Woolwich.
No arrests have been made after the shooting on Coldharbour Lane and an investigation is ongoing.
Keanu Taylor, 25, dies in hospital after shots were fired on Coldharbour Lane on Saturday.
The possibility a drive-by shooting and a stabbing in Brixton are linked is being examined by police.
Suhayb Abdulkadir was found with stab wounds and died at the scene in Leytonstone.
A service is held for Eghosa Ogbebor, who was killed in a stairwell in south London on 2 April.
Michelle Sadio had been at a wake when shots were fired from a car at mourners in north-west London.
