Dog Tracking Evidence: Can That Dog Testify?

by Rick Wetzel on November 18, 2010

Scientific Testimony: Abuse of Discretion Standard

Have you ever had a client located by a tracking dog?  If so, the admissibility of the evidence may be suspect.  A trial court’s decision to admit or exclude scientific testimony is subject to review under the abuse of discretion standard. Sexton v. State, 93 S.W.3d 96, 99 (Tex. Crim. App. 2002). A trial court abuses its discretion when it acts without reference to any guiding rules or principles. Montgomery v. State, 810 S.W.2d 372, 380 (Tex. Crim. App. 1990).

Novel Scientific Evidence Test

Tex. R. Evid. 702 requires the satisfaction of a three-part test before expert scientific testimony is admissible. See Kelly v. State, 824 S.W.2d 568, 573 (Tex. Crim. App. 1992) (holding that admissibility of novel scientific evidence was governed by three-part reliability test: (1) scientific theory must be valid, (2) application of theory must be valid, and (3) technique must have been properly applied); Hartman v. State, 946 S.W.2d 60, 62-63 (Tex. Crim. App. 1997) (applying Kelly requirements to all scientific evidence, whether or not it was novel).

Is The Evidence Reliable?

In determining reliability, courts consider factors such as (1) whether the theory or technique can be or has been tested, (2) whether the theory or technique has been subjected to peer review or publication, (3) the known or potential rate of error, and (4) general acceptance within the relevant scientific community. Nenno v. State, 970 S.W.2d 549, 560 (Tex. Crim. App. 1998), overruled on other grounds, State v. Terrazas, 4 S.W.3d 720 (Tex. Crim. App. 1999).

Standard For Admitting Tracking Evidence

Numerous courts considering the admissibility of tracking and scent evidence rely on three factors to determine whether the Nenno reliability prong is satisfied.  The three factors are: (1) the qualifications of the particular trainer, (2) the qualifications of the particular dog, and (3) the objectivity of the particular lineup.  See Trejos v. State, 243 S.W.3d 30, 50 (Tex. App. – Houston [1st Dist.] 2007, pet. ref’d); Risher v. State, 227 S.W.3d 133, 137 (Tex. App. – Houston [1st Dist.] 2006, pet. ref’d); Winston v. State, 78 S.W.3d 522, 526-27 (Tex. App. – Houston [14th Dist.] 2002, pet. ref’d).

No Standards For Dog Tracking Certification

There are no national or international standards to certify a dog as a “tracker.”  You may well find that the organization that certifies a dog as a tracker is merely a dog club.  This evidence should be thoroughly explored in a pre-trial to exclude the evidence, and to preserve the issue for appeal in the event it is allowed by the trial court.

I like to hear about your experience with dog tracking evidence at trial and/or appeal.

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  1. Review of Erroneous Admission of Expert Testimony
  2. Was The Witness An Accomplice? Maybe Not.

{ 1 comment… read it below or add one }

allenrogers December 2, 2010 at 12:36 am

Rick, if the K9 officer says the dog identified the defendant based on a shirt, doesn’t the state have to prove the shirt belonged to the defendant?


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