A travel card holds the key to convicting a violent offender after a spate of random stabbings. Police taser the man whilst he brandishes weapons on a public street. Also, a bureau de change receipt helps put a pair of thieves behind bars after they subject their victim to a terrifying ordeal.

A thief who prowls for victims on social media is locked up, thanks to the sheath of his knife, and a plea for help scrawled on a £10 note puts two kidnappers behind bars.