Mr Tyndall had planned to a send a copy of the report to the General Medical Council, the body which regulates doctors, because "Mr Y seemed disinclined to believe he had anything to learn".

BBC: Allan King

The body was found at about 14:00 BST in woodland off the Nant-y-Garth pass in north Wales.

BBC: Georgia Williams

Instead, to judge by the most comprehensive study on the reliability of forensic evidence to date, the error rate is more than 10% in five categories of analysis, including fiber, paint and body fluids. (Meaning: When the expert says specimen X matches source Y, there's a 10% probability he's wrong.) DNA and fingerprints are more reliable but still not foolproof.

FORBES: Forensic evidence doesn't always tell the truth.