One teenager disappears after making sure her friend gets home safely. For nine months, police have no body, no suspect, and almost no evidence. But that all changes in a moment. Unexpected specialist are pulled in to examine every little detail including pollen, insects, carpet fibers and more. In today's case, one of the most extraordinary forensic investigations ever assembled slowly uncovers a killer who thought he'd hidden every trace of his crime.

This is the case of Leanne Tiernan

• BBC News
•  Crime+Investigation UK 
•  Yorkshire Post 
•  Yorkshire Evening Post 
• A Town and Country Murder (Season 3, Episode 8: "Leanne Tiernan") 
•  Wikipedia (used for cross-referencing dates and publicly documented case information)