Iain transports us to 1858 Bradford – then the world's wool capital, where confectioner William Hardaker ("Humbug Billy") unknowingly sold arsenic-contaminated sweets that resulted in one of Britain's most devastating mass poisonings.

Plus your emails feature a burglar delivered to police by Batman, a theory about D.B. Cooper, and the street poet who challenged developers with a can of spray paint!

Murder They Wrote with Laura Whitmore and Iain Stirling is available twice a week on BBC Sounds. Subscribe now so you never miss an episode. Email us at [email protected].

This episode has been updated to clarify the number of deaths in the Humbug Bill case.