Writer turns detective to investigate Glasgow's real life crimes

Denise is one of four authors taking part in Once Upon a True Crime, a brand new show which delves into the chilling stories which sparked bestselling novels.

She will guide viewers through the case of one of Scotland’s most notorious serial killers, Peter Manuel, which inspired her novel The Long Drop.

Nicknamed the ‘Beast of Birkenshaw,’ Manuel was convicted for the murders of seven people in the mid-1950s, and hanged at Glasgow’s Barlinnie Prison for his crimes; the second to last prisoner to die at the Barlinnie gallows before the death penalty was abolished in the UK.

Manuel terrorised the city of Glasgow during a two-year killing spree.

Denise unearths the story of a man who killed without conscience and delves into an unusual relationship between Manuel and William Watt, whose family was murdered by the serial killer.

Glasgow also features in Douglas Skelton’s episode, which examines the city’s notorious Ice Cream Wars, a tense gangland turf war which inspired his novel Blood City.

Skelton revisits the gritty scenes of 1980s Glasgow, where conflicts and corruption strained the city’s east end as rival criminal organisations competed to sell drugs and stolen goods from ice cream vans.

At a time when poverty was rife in the city and fuelled violence, rival ice cream van crews battled for control over east end territories.

What began with slashed tyres and smashed windscreens escalated into a horrific mass murder, with fire-raising attack that killed a family of six.

Skelton delves into the tensions between the gangs, a 20-year battle to prove the innocence of two men convicted and the unsolved case that still haunts Glasgow.

The other authors to feature in the series are Peter James, author of Babes in the Wood and Mark Billingham, author of Their Little Secret.

International bestseller Peter James revisits the shocking so-called Babes in the Wood murders in Brighton of 1986.

It was a chilling case of two young girls, Karen Hadaway and Nicola Fellows, who were sexually assaulted and killed, and it became one of the largest and longest-running inquests in Sussex police history.

Mark Billingham delves into the story of two of Britain’s most infamous serial killers, Ian Brady and Myra Hindley, whose killing of five children became known as the Moors Murders.

READ MORE: Glasgow's 'forgotten' Nobel Prize winner who helped women get vote

Their twisted relationship influenced his best-seller Their Little Secret which features his award-winning, fictional Detective Tom Thorne.

In each episode, the writers retrace the steps of the killers and victims, taking viewers through every twist and turn in the story.

With unprecedented access to experts, witnesses and journalists who covered each case, the murders are pieced together and new, untested theories surface in attempt to resolve mysteries that remain.

Once Upon a True Crime starts on Crime+Investigation on April 25.