Two people have been killed and another two injured in a spate of attacks across London.
A teenage boy was found with fatal stab wounds on Church Road, Havering, at 18:41 BST on Friday - 10 minutes later, another boy was found with stab injuries on nearby Retford Road.
A man was then pronounced dead in Gillett Square, Dalston, just before 01:00 after reports of shots fired.
A man, 18, is also critical after being stabbed in Woolwich on Friday.
The boy found in Church Road died at the scene and the boy in Retford Road was taken to hospital.
Three people have been arrested in connection with those stabbings, the Met said.
Homicide detectives have been informed of the death, although a murder investigation is yet to be officially launched.
The man pronounced dead in Dalston was found with "serious injuries", but officers said they were still establishing the "exact nature" of the injuries.
A crime scene remains in place and no arrests have been made.
The Met said the 18-year-old man attacked in Woolwich was stabbed in Marine Drive on Friday afternoon and remains in a critical condition in hospital.