midlands police also show a nine-year-old girl of 13 became one of britain 's youngest murderers after he was jailed for at least 12 years for killing a woman he had just mugged by stamping on her face so hard it left a footprint on her cheek .
they include 41 nine-year-old boys investigated for crimes last year including five suspected of sexual offences , according to the details released after a freedom of information act request .
between 2009 and 2014 a total of 617 youngsters aged under ten in the region either committed , of were suspected of committing , a crime , according to the details .