Teen killer filmed passing lie detector test

A Scottish man convicted of murdering his girlfriend when they were both aged 14 had declared his innocence in a landmark prison video released on YouTube.

In January 2005 Luke Mitchell, 24, was found guilty of the brutal stabbing murder of his girlfriend Jodi Jones in 2003.

Another innocent behind bars?

Another innocent behind bars?

He has consistently denied killing her and was filmed taking a polygraph test in April last year after demanding to be put under the scrutiny of the lie detector for years.

The video was only released today as it was filmed on the grounds of Scotland’s maximum-security Shotts Prison and needed to await the approval of the Scottish Prison Service.
It is believed to be the first time a video had been published of convicted criminal taking and passing a lie detector test while in prison.

The video shows Mitchell sitting in a chair with his eyes closed as he answers questions about the murder of his teenage girlfriend.
Mitchell responded “no” when asked if he was present when Jodi was stabbed and “no” when asked if he had stabbed her.

British Polygraph Association secretary Terry Mullins, who interviewed Mitchell, said the convicted killer had passed the test. “I’m certain of the test result. It’s absolute,” Mr Mullins said. “I can’t believe Luke Mitchell was convicted on the evidence that was available.”

Jodi Jones was found murdered near her home in Midlothian in 2003 after she had gone out to meet Mitchell. Her throat was slashed and she had post-mortem cuts to her eyelids, right cheek, left breast, abdomen and right forearm. Mitchell has always denied committing the murder and his mother has said he was with her when Jodi was killed.

Scottish courts do not allow polygraph tests to be submitted as evidence but a report on the test has been included in Mitchell’s submission to the Scottish Criminal Cases Review Commission which investigates potential miscarriages of justice and can recommend an appeal  (Source article).

I know from my own research how ambiguous polygraphs can be as they tend to measure the autonomic nervous system (skin temperature, blood pressure & heart rate) however in my opinion tend to miss some ANS clues such as frequency of breathing, amount of swallowing and pupil dilation as well as other behavioural clues. Due to this, the polygraph has sent a number of innocent people to prison who “failed the polygraph” for various reasons other than being guilty of (for example) murder (eg. people can fail because they are afraid of being disbelieved). The polygraph detects stress, it does not directly detect lies (Don’t get me wrong, I think the polygraph is great and works very well in many cases).

Issues with taking a polygraph years later (in this instance 8 – 10 years later) is that through continuous repetition or as a coping mechanism, people can come to believe something that isn’t true – and subsequently will pass a polygraph.

So, is Luke Mitchell innocent? Personally, I hope so. I’d like to see some interview footage and would be happy to go through police interviews should they be available to make an independent assessment.

This entry was posted in Analysis, Evaluating Truthfulness and Credibility, Psychology and tagged , , , , , . Bookmark the permalink.

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