Prosecutors ask CID, NCIS, OSI, CGIS agents all the time why they didn’t believe the accused in the interrogation. The answer often is a variant of, “he was nervous.”
First they are told and usually escorted to the LE office. The escort won’t tell them why or what’s going on. They then have to wait the appropriate time in the waiting area to heighten the tension. I was reminded of this by a post from fourth amendment blog.
Continuing defendant’s open container stop for a beer can because he was nervous was unreasonable. “[L]ights and sirens at three o’clock in the morning could make a saint nervous without shedding any light at all on whether there was alcohol in the can.” United States v. Hemingway, 2013 U.S. Dist. LEXIS 34517 (D. D.C. March 13, 2013).*
I think the same applies to law enforcement interrogations. A LawFirms.com blog starts out:
Talking with police officers is usually one of the more stressful encounters we have in our lives, and one that we typically avoid at all costs. Even when we’ve committed no crime, it can be nerve racking, but when we’re guilty it’s much worse.
Of course there are other “indicia” offered as to why they disbelieved the accused. But, cautions those guru’s of interrogation (The Reid):
In conclusion, because laughter and humor relieve anxiety, it is common for both truthful and deceptive suspects to engage in these behaviors during an interview. The mere presence of laughter or attempted humor during an interview should not be considered a behavior symptom of deception.
The Reid also points out that:
Furthermore, when accused of wrong-doing, the tendency to deny opportunity, access, motive and propensity occurs within both innocent and guilty suspects.
You can read more about interrogations at The Reid. Why is it valuable for a defense counsel to read The Reid. Well of course it’s an aid in understanding how law enforcement may have coerced a confession, or got it wrong. But, it’s also an invaluable guide in how you interview your own client and witnesses. I’m not saying you become an investigator or accusatory toward your client or witnesses. The idea of interrogation techniques is to get information. I know law enforcement is only looking for the confession, but you have a broader purpose.
The Reid’s final caution today is:
Some research has attempted to identify specific cues associated uniquely with lying (nature of eye contact, micro tremors in the voice, unique facial expressions, etc.). These efforts have not produced accuracies much above chance levels. . . . Not all innocent or guilty suspects respond exactly the same way when questioned about a crime. . . . In conclusion, many laboratory studies investigating the validity of behavior symptom analysis are flawed because they attempt to identify specific behaviors that reveal truth or deception; indeed, there are no behaviors unique to truth or deception.
Of course that leads to my favorite law enforcement response – confirmation bias.