first aid

"I want to thank school staff who administered first aid until paramedics arrived to take over and transport her to hospital, where sadly, she later passed away," she added.

The Met said officers provided "immediate first aid" at the scene before paramedics arrived.

He thanked members of the public who provided first aid to Mr Rivero, and added: "Their witness statements were also crucial in helping us arrest the girls within hours."

A woman, who told the BBC she helped administer first aid to the teenager, said there had been "shock and panic" at the scene.

Police officers helped ambulance staff to administer first aid in the house.