蜜芽传媒

'Happy birthday and all the best', reads a birthday card received by a family, tricked into believing their murdered relative is still alive. Around that time, a human torso dumped at a Salford beauty spot sparks a murder investigation.

Police trawl CCTV looking for a suspect as more body parts and DNA are uncovered at further six locations in Greater Manchester. The police investigation starts to close in on a man, identified through an extensive trawl of CCTV, struggling to carry a large bag.

How did the police piece together the evidence to discover the ultimate betrayal? What could the victim鈥檚 family reveal about their last contact? And how did a chance sighting lead to the perpetrator getting caught?

A journalist, a forensic psychiatrist and a former police detective delve into the details of the murder investigation, determining how the crime was committed, explaining what police work was involved and evaluating what it takes for someone to commit such a 'heinous' crime.

If you have been a victim of crime, details of help and support are available at bbc.co.uk/actionline.