Wolf Inside the Chicken Coop – Visiting the DPS Crime Lab

Today DPS opened up their doors allowing us an inside look at their crime lab.  In particular we were given presentations on DNA, Ballistics, Evidence Reception, Breath Alcohol and Blood Alcohol Testing, and Drug Testing.  The experience was one every criminal defense attorney should undertake.

Receiving Evidence

Why the method of receiving evidence is important?

A major concern with evidence of any kind, but especially biological evidence is contamination.  Contamination can come from a number of sources.  The receiving department has the responsibility of ensuring the integrity of the evidence has not been compromised.  Compromised evidence can lead to wrongful convictions.  Under the law the chain of custody must be known before any evidence is admitted into court (i.e. who handled the evidence and when did they handle it).  The receiving department assists in ensuring the chain of custody is accurate and proper.

What to look for:

How was the package sealed?

• How is it taped?
• Is there evidence tape?
• Were staples used?
• Is the package torn or ripped?
• Is the package opened?
• Is there a proper chain of custody?

 Trace Evidence

Trace evidence occurs when objects contact.  Examples include, hairs, paint, shoe prints, fingerprints, glove prints, etc.  Below are some of the machines used by DPS to attempt to reconstruct the crime scene using trace evidence.

  

Breath Test

While there has been a bit of delay for the release of the Intox9000, the anticipated release date is January 1, 2016.  The Intox9000 will replace the Intox5000, which has provided breath alcohol samples since the early 80s.  While there are a few new gadgets on the Intox9000, in essence it is simply a more user friendly version of the Intox5000.  Meaning there are still a number of issues concerning its accuracy and reliability.

During this presentation it must be noted, when asked about the delay on the Intox9000, it was denied.  Also, when asked by an individual if the Intox machines were in vehicles, the DPS employee responded they would never put one in a car.  This is 100% false, as they have done just that (known as the BAT Van).

Blood Alcohol Testing

The Gas Chromatograph – Flame Ionization Detector (GC-FID) pictured below is used to qualify and quantify alcohol in blood. This machine is based on separation science.  As an example, picture a sloped driveway.  You are standing by the garage with a number of different sports balls in front of you (e.g. basketballs, footballs, soccer balls, baseballs, golf Balls, etc.).  As you turn the blower on and point it towards the balls, they will begin traveling toward the bottom of the driveway.  Eventually they will all reach the base of the driveway, doing so at different speeds.  Think of molecules in blood as those balls.  The machine is able to identify the molecules (i.e. ethanol) via the speed at which they travel through the machine.  Once the molecule has been qualified (identified), it can then be quantified.

Of note:  DPS employees listed on the dry erase board the highest BACs of the year.  Directly in front of that board was Garriott’s Medicolwegal Aspects of Alcohol,  a book written by the leading scientists regarding alcohol.  The three BACs listed on the dry-erase board were all well over 0.40.  When asked, “0.40?  Shouldn’t the person be dead?”, the DPS employees response, “Yes, they should be.”  Yet the result was considered valid and business as usual? Despite the leading scientists stating death is a real possibility at 0.30? Disturbing answer.

Drug Testing

After a positive presumptive test.  Drugs are then run through the Gas Chromatograph – Mass Spectrometry (GC-MS) for a confirmatory test.  Similar to blood alcohol testing this science is based on separation.

 

Ballistics

Think gun residue, shooting distance, serial # restoration, bullet cartridges, etc.

DNA

Specifically fingerprints and bodily fluids used to obtain information on potential suspects.

While it was difficult not to turn the presentation into a colorful cross-examination, the experience was both invaluable and informative.  We appreciated the opportunity to take a look inside the chicken coop.