Police have named a woman allegedly stabbed to death by a knifeman wearing a Phantom Of The Opera-style mask in east London.
A spokesman said Sehrish Waqar Sheikh was aged 23 and from Dagenham.
The young woman died after being attacked on Monday evening as she worked at St George's international college in Plaistow, east London.
Ken Bristow, a taxi driver who works opposite, said a witness - believed to be a fellow employee at the school - had rushed from the scene, screaming: "He's killing her."
Mr Bristow added: "He was stabbing her upstairs at the college - my close friend was working next door when it happened. My friend rushed up there after a woman came running out. But by then the victim was dead."
He added: "I was told she must have been stabbed dozens of times. There was blood everywhere. After police and ambulances arrived, the attacker was taken away. He had been wearing a mask and cloak."
A 29-year-old man has been arrested on suspicion of murder.