Three girls and a person had been fatally stabbed in the London borough of Southwark early Monday, the police stated.
A suspect was arrested and is in custody, the police added.
The police say they consider that the attacker and the victims knew one another, however no info was instantly out there on the circumstances surrounding the killings.
Officers responded to studies of a disturbance at 1:40 a.m. on Delaford Road in Southwark. After forcing entry, they discovered 4 individuals inside with what seemed to be stab wounds, the police stated.
The 4 individuals had been pronounced lifeless on the scene, the police added.