Dog Tracking Evidence: Limitations of CALCRIM 374
August 6th, 2018

CC 374 includes the following language:


Before you may rely on dog tracking evidence, there must be:


  1. Evidence of the dog’s general reliability as a tracker;


  1. Other evidence that the dog accurately followed a trail that led

to the person who committed the crime. This other evidence does

not need to independently link the defendant to the crime.


In deciding the meaning and importance of the dog tracking evidence,

consider the training, skill, and experience, if any, of the dog, its trainer,

and its handler, together with everything else that you learned about the

dog’s work in this case.


Furthermore, the CC 373 Bench notes state that “whenever they are

used to prove the identity of a defendant.” [Citation to People v. Malgren (1983) 139 Cal.App.3d 234, 241.]


There are two concerns with this CALCRIM instruction and Bench Note.


First, CALCRIM fails to acknowledge that dog tracking evidence is subject to foundational scrutiny before it may be presented to the jury. As Malgren observed, there are “stringent foundational requirements which must be met before such evidence is admissible at all….” (Ibid; see also People v. Mitchell (2003) 110 Cal.App.4th 772, 790-794.) Thus, the judge’s duty to instruct does not arise if the evidence is challenged and excluded at a foundational EC 402 hearing. (See e.g., People v. Mitchell, supra, [dog scent evidence was admitted in error]; cf., Aguilar v. Woodford (9th Cir. July 29, 2013) 725 F.3d 970 [First-degree murder conviction vacated because of Brady violation resulting from failure of the prosecution to disclose that the dog had a history of making mistaken scent identifications].)


Second, depending on the circumstances, it may be appropriate to separately instruct the jurors on factors not included in CC 374.


Sample instruction #1:

In evaluating the accuracy of the dog scent discrimination evidence and the weight, if any, to give this evidence, the facts to consider include, but are not limited to, the following:

  1. The training, proficiency, experience and proven ability, if any, of the dog, its trainer and its handler;
  2. The manner and circumstances surrounding the collection of the dog scent discrimination evidence;
  3. Any evidence on the subject of whether the dog scent discrimination evidence was or was not contaminated; and
  4. The manner and circumstances in which the evidence was presented to the dog and its handler, and the reaction, if any, of the dog, as described by the handler, to the dog scent discrimination evidence.


It is appropriate to instruct the jurors on specific factors relevant to a given factual issue. (See e.g., People v. Wright (1988) 45 C3d 1126, 1149 [eyewitness identification factors]; People v. Gurule (20020) 28 C4th 557, 660 [defense right to pinpoint instruction on defense theory]; U.S. v. Pierra (9th Cir. 2001) 254 F3d 872 [same]; see also FORECITE F 315.1.2 Inst 2.) The CALCRIM instructions affirm the propriety of such instructions. (See e.g., CC 105/CC 226 [witness factors]; CC 330 [child witness factors]; CC 331 [person with developmental, cognitive, or mental disability]; CC 441 [whether solicitation constitutes multiple crimes]; CC 549 [felony murder; one continuous transaction]; CC 1156 [intent to commit prostitution]; CC 1201/CC 1215 [kidnapping: substantial distance]; CC 2110 [manner of driving is factor to consider re: driving under the influence]; CC 2840 [failure to file tax return is factor to consider]; CC 2842/CC 2843 [another factor to consider re: unreported taxable income].)



Sample Instruction #2:


In evaluating the dog tracking evidence the factors for you to consider, if applicable, include, but are not limited to, the following:

  1. Whether or not the handler was qualified by training and experience to use the dog.
  2. Whether or not the dog was adequately trained in tracking humans.
  3. Whether or not the dog has been found reliable in tracking humans.
  4. Whether the dog was placed on the track where circumstances have shown the guilty party to have been.
  5. Whether or not the trail had become stale or contaminated.

CALCRIM 374 fails to include potentially relevant factors regarding dog tracking evidence. The above instruction, which is based on People v. Gonzales (1990) 218 CA3d 403, 407, more specifically alerts the jury to the considerations affecting the weight of such evidence.

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