A teenage rape victim remains under heavy sedation after being doused in acid by her attackers.
The 16-year-old schoolgirl suffered horrific burns at an empty house in Tottenham, north London.
Detectives believe the acid — possibly drain cleaner — was used to try and destroy DNA evidence.
They think the victim may have been kidnapped by a gang of youths who then took her to the house before attacking her.
Officers from the Metropolitan Police's Operation Sapphire unit, which specializes in investigating sex attacks, are responsible for the inquiry.
A spokeswoman said: "We were called at 8.20pm on Wednesday January 9 to reports of a disturbance at an address in Anthill Road, N15.
"Officers discovered the victim suffering burn injuries. London Ambulance Service attended and took her to hospital where she remains stable."
The victim — being treated in a specialist burns unit — is still too ill to talk to police.
Senior police officers are paying close attention to a growing trend of criminals who possess a greater awareness of forensic evidence and try to cover their tracks.
A 17-year-old boy from Tottenham has been charged with rape and grievous bodily harm over the incident.
He will appear before magistrates later today.