In a South London police station, a homeless man kills hishis cellmate. Police interview 53-year-old Kieran Kelly, and then he calmly confesses to decades of murders, many on the London Underground.

In a South London Police Station, officers are shocked to discover a man has been murdered in a locked cell. The suspected killer is his cellmate, a homeless man called Keiran Kelly, in custody for theft. Police interview 53 year old Kelly, who has a long rap sheet for petty crimes, and he calmly confesses to killing the man in the cell, but detectives are unprepared for what comes next.—Woodcut Media