A 17-year-old girl has suffered serious head injuries and stab wounds in an attack in north London. The teenager was assaulted behind garages at the rear of Wendover House in Palmerston Road, Palmer's Green, on Monday.
She was taken to a hospital where she is said to be in a critical condition.
Det Ch Insp John Macdonald said: "We hope there will have been people who may have seen somebody acting suspiciously."