Baltimore Tunnel Threat Assessed by Polygraph

[George W. Maschke]

Following closely upon the Intelligence Community's reliance on the pseudoscience of polygraphy to bolster the credibility of an informant who reported a bogus threat to the New York subway system, the lie detector has again been relied upon, this time to downplay the credibility of an informant who reported an alleged plot to attack traffic tunnels in Baltimore, Maryland. ABCNews.com reports in an article by Brian Ross titled, "Another Unnecessary Terror Scare?":

Oct. 18, 2005 —  A love triangle may have led to today's terror scare that closed two major tunnels in Baltimore.

Federal officials tell ABC News they raised questions on the credibility of the informant's information after he failed a lie detector test this past weekend.

At first, the informant, who is in prison overseas, disclosed the names of eight Egyptians who are connected to an Arab grocery store in Baltimore. Officials now say he may have been trying to cause trouble because one of the eight had become romantically involved with his girlfriend.

While there may be legitimate questions about the informant's motives for implicating the eight Egyptians, his polygraph chart readings should be given no weight whatsoever in assessing his credibility. They are of no more probative value than tea leaf or astrological chart readings. Moreover, polygraphy has an inherent bias against the truthful to begin with, and in cases such as this one, where the subject is under arrest and may have been subjected to interrogation and sensitized to the relevant issues beforehand, the risk of a false positive increases.

Like the New York subway case, this would appear to be another case where a meaningful Concealed Information Test (alternatively known as a Guilty Knowledge Test) might be constructed for those implicated by the informant. If the FBI plans on using polygraphs to interrogate the Baltimore eight, it is to be hoped that they will have the wisdom to use this theoretically sound technique, rather than the completely invalid "Control Question Test."

For more on the Baltimore tunnel threat case, see "Gridlock, But No Bomb" by Baltimore Sun reporter Matthew Dolan.

[George W. Maschke]

In an article titled, "Officials: Tunnel threat tip came from Netherlands" CNN.com reports:

Wednesday, October 19, 2005 Posted: 1755 GMT (0155 HKT)

BALTIMORE, Maryland (CNN) -- Information about a possible threat that shut down the Baltimore Harbor Tunnel on Tuesday came from a prisoner in the Netherlands, two federal sources said.

The prisoner was given a polygraph test last weekend, but the results were inconclusive, one source said.

Some of the answers given during the test were seen as deceptive, officials said.

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