A 17-year-old was being held Wednesday in Brazil for allegedly knifing thirty men to death.

The schoolgirl stunned cops by owning up to a serial killing spree that started when she was a 15-year-old.

She told detectives she wanted to confess before she turned 18 and could be tried as an adult.

The girl — too young even to be named — said she began targeting men in her home city of Sao Paulo, Brazil "for money, revenge and to bring justice".

She allegedly even smiled as she reeled off her list of victims — which is feared to make her the world's most prolific teenage serial killer.

Click here for more on that story from The Sun.