Monday, October 16, 2006

He's Not Just a Cop; He's a Human Lie Detector

So, I was reading some police reports on one of my cases last week, and was fascinated with some of the detail the detective provided regarding his observations of various suspects as he interviewed them. As he was questioning one suspect, he observed that he appeared nervous and was breathing rapidly. On top of that, he saw that his carotid artery was beating strongly and rapidly and estimated his pulse at over 100 beats per minute. With another suspect, he observed several signs of deception such as prefacing answers to questions with "honestly" and "to tell you the truth." Another suspect had a noticeable tremor in his right hand as he answered questions. Has anyone ever seen comments like this in a police report before? It was a first for me. I was especially interested in his close observation of one man's carotid artery and his estimate of his pulse. It's a wonder he could keep track of what the man was saying in between focusing on his artery and taking his pulse visually. Is it just me or does it seem like this detective has been to some class recently on human lie detection?

3 Comments:

Blogger Ruth said...

We have a cop like this. I had a dwi case where the intoxicated gentleman was changing his baby's diaper in a running car (it was December) while waiting for his wife to get out of the convenience store. The cop testified in all seriousness that he "heard the transmission click into reverse" and "knew through his training and experience" that the gentleman was going to "careen through the parking lot at a high rate of speed with an unrestrained child in the car." There was an acquittal.

10/16/2006 6:33 PM  
Anonymous Anonymous said...

Sure they get training in this stuff. The danger isn't that a cop will testify that these signs showed deception; judges will keep the conclusion out. The problem is when prosecutors say all they're doing is asking the cop for the observations (carotid artery pounding away, etc.) and let the jury decide what it means. That's more likely to sell. So, defense: BRIEF IT!

10/16/2006 7:42 PM  
Anonymous Anonymous said...

His technique is called 'lying'. Since his is the only 'record' of the interview, there is no way to challenge his 'facts'.

If he was telling the truth about the pulse rate, would not the subject have noticed him holding and operating the stopwatch, and staring for 30 seconds at his neck?

Yes, obviously, he's lying. He's just more devious than you're used to.

Get used to it.

10/17/2006 3:54 AM  

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