Police DUI Experts Instructed to Commit Perjury

Posted by Lawrence Taylor on March 17th, 2006

A key witness in most DUI trials is the prosecution’s crime lab blood-alcohol expert, often called a forensic toxicologist.  He will explain to the jury what the breath or blood test results were and what they mean; what the probable blood-alcohol level was when the defendant was driving; and that the breathalyzer was properly maintained, calibrated and in proper working order at the time of the test.  To say the least, the honesty and accuracy of this expert’s testimony under oath is critical to the outcome of the trial.

Unfortunately, this witness is often less than honest and objective in his testimony.  As a law enforcement employee, he sees his job as helping the prosecutor to secure a conviction — and commonly tailors his testimony accordingly.

The same is true of phlebotomists (technicians who draw a blood from the suspect) who testify as to the procedures used for drawing the blood,  identification of the blood sample, etc.  The expertise and honesty of this witness is equally critical in a DUI trial.

The following is a complete and verbatum (emphasis in the original) copy of a set of instructions given by the San Diego Police Department to their blood-alcohol technicians testifying in a drunk driving trial (presumably, a different script exists for toxicologists):


                                             COURT TESTIMONY

You will be asked your name.

You do not have to remember drawing [blood from] the particular defendant.  Just say you draw many patients each day you work and it is impossible to remember each one.

You may be asked how you draw the blood.  It is the standard procedure you follow for ALL blood draws, EXCEPT that you use a NON-ALCOHOLIC antiseptic wipe (Benzalkolium) to cleanse the phlebotomy site.  You ALWAYS follow the same procedure for every blood draw.  The blood is drawn into grey top tubes provided by the San Diego Police Department.  The tubes contain an anticoagulent (Potassium Oxylate) and a preservative (Sodium Fluoride).  You check the tube for the presence of a loose, slightly pink powder before you use it.  After you fill the tube with blood, you invert the tube 10 times to mix the blood with the anticoagulent/preservative.  You will always mix any tube with an anticoagulent 10 times (you count the inversions).  The important things to remember is that you always follow the same procedure, so even though you don’t remember this particular individual, you know that you drew the person following our standard procedure.

The suspect is identified by the police officer and, when possible, you check the ID or ask the suspect their name.  The police officer completes the label with the suspect’s name, DOB, etc.  You put your name, date, draw time, and place on the label and place the label on the grey top tube.  You then place the grey top tube in the plastic chain-of-custody tube, put the cap on it, and seal it with the sealing tape provided by the SDPD.  You then hand it to the officer and he takes charge of it.


These instructions on what to say in trial are given to law enforcement witnesses  testifying under oath.  The witnesses are told to “testify” as instructed — not as to what they actually did and what they know to be true in a specific case. 


(Thanks to San Diego attorney Cole Casey.  A fellow attorney in a recent DUI trial asked a phlebotomist outside the courtroom what he was reading just before going in to testify; surprisingly, the witness showed him — and the attorney shared the document with Mr. Casey.)

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