Lie detectors being used on sex offenders in Norfolk
PUBLISHED: 12:09 09 November 2019 | UPDATED: 18:27 09 November 2019
Sex offenders are being given lie detector tests in a bid to assess the risk they pose to children.
And Norfolk Police have said they may roll out the use of polygraph tests for evidence in court or even on its own staff.
The force trained up three members of staff in January as part of the American Polygraph Association, and bought three lie detector kits for around £15,000.
And Norfolk is now one of the "most active users of the tactic" in the country. Just four other forces in the UK currently use lie detector tests.
The constabulary says a study being conducted at Kent University, published this month, could open up potential for polygraphs to be used in court, despite concerns over their reliability.
Since January registered sex offenders have been offered polygraph tests as part of their risk assessment.
Officers said if they refused they could be classed as a higher risk.
To date 116 sin Norfolk have taken the polygraph test, and 65 have refused.
A polygraph records changes in a person's blood pressure, pulse, respiration and skin conductivity.
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The belief is that deceptive answers will produce physiological responses that are different from those associated with non-deceptive answers.
A major change in any pattern, known as a "response conflict", is said to be a sign a person is lying.
The tests are not 100pc accurate, but are said to have a high accuracy level.
Evidence is not generally accepted in criminal courts in the US and most of Europe.
Police said the tests were not being used to determine guilt or innocence, but to "manage future risk".
Det Chief Supt Christopher Balmer said in a report: "It is important to stress that the polygraph tactic is just one of a number of options available within the sex offender risk management process."
He added the results had helped safeguard children in the county.
"In nine cases the team's work and analysis has led to direct positive interventions that have safeguarded children," he said. "These responses have included such actions as the disclosure of an individual's previous convictions to better inform those they are associating with."
Det Chief Supt Balmer added the findings from the Kent University study "may well open up further opportunity around the use of the polygraph test in a wider range of policing activity".
He said: "Beyond the obvious consideration as to its validity in court it offers the opportunity to scope its inclusion in other risk assessment processes both for the persons we interact with as well as our own staff."
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