DUI & Criminal Defense

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Failure to Preserve Blood for Independent Testing

The basic rule is the government has no duty to gather exculpatory evidence for you.  However, Arizona is one of the few states that, under certain circumstances, requires the police to gather exculpatory evidence.  In practice, this means that when the police seize a sample of blood from a person suspected of DUI, they must take enough of the sample for that person to have a laboratory of their own choosing analyze it.  

This duty placed upon the government arises from the right to Due Process at issue in Arizona DUI cases.

  • State v. Treadway, 116 Ariz. 163, 568 P.2d 1061 (1977) (the general rule in Arizona is that the State has no duty to gather evidence for the defense.
  • State v. Walters, 155 Ariz. 548, 551, 748 P.2d 777, 780 (App. 1987) (State has duty to preserve potentially exculpatory evidence “that is obvious, material and reasonably within its grasp”);
  • State v. Dunlap, 187 Ariz. 441, 452, 930 P.2d 518, 529 (App. 1996) (Due Process does require the State to preserve evidence of “constitutional materiality.”

When is Due Process Violated?

To show the government has violated Due Process in a DUI case you must prove they acted in bad faith.  This means the police must know the value of the evidence at the time it was lost or destroyed.

  • Arizona v. Youngblood, 488 U.S. at 57–58, 109 S.Ct. at 337, 102 L.Ed.2d at 289; State v. Youngblood, 173 Ariz. at 508, 844 P.2d at 1158. (Due Process is violated when a defendant shows the state had acted in bad faith in failing to preserve the evidence);
  • State v. Walker, 185 Ariz. 228, 238, 914 P.2d 1320, 1330 (App.1995), quoting Arizona v. Youngblood, 488 U.S. at 56 n., 109 S.Ct. at 336 n., 102 L.Ed.2d at 288 n. (A determination of bad faith “‘must necessarily turn on the police’s knowledge of the exculpatory value of the evidence at the time it was lost or destroyed.’”);
  • State v. Dunlap, 187 Ariz. 441, 452, 930 P.2d 518, 529 (App.1996) (state must preserve only evidence that could be expected to have significance in suspect’s defense).
  • Youngblood v. Arizona, 488 US 51 (1988) (“We think that requiring a defendant to show bad faith on the part of the police both limits the extent of the police’s obligation to preserve evidence to reasonable bounds and confines it to that class of cases where the interests of justice most clearly require it, i.e., those cases in which the police themselves by their conduct indicate that the evidence could form a basis for exonerating the defendant.  We therefore hold that unless a criminal defendant can show bad faith on the part of the police, failure to preserve potentially useful evidence does not constitute a denial of due process of law.”).

Arizona has recognized the inherent exculpatory value of biological samples (i.e. blood, breath or urine) seized in DUI cases.  Accordingly, a person suspected of DUI has a separate and distinct due process right to obtain an independent test. 

  • Mack v. Cruikshank, 196 Ariz. 541, 546, 2 P.3d 100 (App. 1999) (… [A] DUI suspect has a separate and distinct due process right to obtain an independent test at the suspect’s own expense to refute the state’s evidence, whether from scientific tests or otherwise…. Although it is a constitutional due process right, Smith v. Cada, 114 Ariz. 510, 562 P.2d 390 (App.1997), it is codified in former 28-692(H), now 28-1381(M), which was adopted at the same time as the implied consent law. 1969 Ariz.Sess.Laws, ch. 41, § § 1 and 2.0);
  • Montano v. Superior Court, 149 Ariz. at 389, 688 P.2d at 275 (1986). (It had been held that the Due Process Clause of the Arizona Constitution guarantees to a DUI suspect a “fair chance to obtain independent evidence of sobriety essential to his defense at the only time it [is] available.”);
  • Baca v. Smith, 124 Ariz. 353, 604 P.2d 617 (1979) (In DUI cases, where the government collects biological evidence to determine guilt, they havea duty to both collect and preserve evidence for independent testing by the defense).


Baca v. Smith, 124 Ariz. 353, 604 P.2d 617 (1979).

In Baca, the Arizona Supreme Court ruled that the police had to offer to collect and preserve a second breath sample in a field collection unit whenever they chose to give breath tests, recognizing that such samples are crucial pieces of evidence without which the defendant would be unable to effectively challenge the accuracy of the test results offered against him. 

Scales v. City Court of City of Mesa122 Ariz. 231, 594 P.2d 97 (1979).

Subsequently, in Scales v. City Court of City of Mesa, 122 Ariz. 231, 594 P.2d 97 (1979), the Arizona Supreme Court condemned the state’s practice of routinely destroying breathalyzer test ampoules, finding the “destruction of [which] deprives the defendant of a crucial source of evidence with which to attack the validity of the test reading…”  Scales v. City Court of City of Mesa, 122 Ariz. 231, 234, 594 P.2d 97 (1979).  

State v. Perez, 141 Ariz. 459, 463, 687 P.2d 1214 (1984).

Thus, the government has a duty “to ensure the preservation of evidence it is aware of where that evidence is obviously material and reasonably within its grasp.”  

State v. Wiley, 144 Ariz. 525, 698 P.2d 1244 (1985).

In reviewing whether a defendant has been denied a fair trial by the destruction of evidence, courts must look to the circumstances of each particular case.  

State v. Day, 148 Ariz. 490, 715 P.2d 743 (1986).

If the state has acted in bad faith or connivance or the defendant is prejudiced by the loss, the destruction of evidence deprived that defendant of Due Process.   

State v. Kemp, 168 Ariz. 334, 813 P.2d 315, 335-337 (1991).

In State v. Kemp, 168 Ariz. 334, 813 P.2d 315, 335-337 (1991), the Arizona Supreme court reaffirmed its prior holding in Baca, stating:

Once again we are presented with a due process question in a DWI case. The State argues that the court of appeals created a new right that due process does not require.  It claims that due process does not require law enforcement officers to advise a DWI defendant that he may obtain a portion of a blood sample seized because (1) blood testing leaves a portion of the seized blood sample available for independent testing by the defendant, and (2) blood testing is so accurate that an independent test would not provide exculpatory evidence…[B]ecause blood testing leaves a portion of the seized blood available for independent testing by the defendant, we need not address the State’s argument regarding the accuracy of blood testing.

State v. Kemp, 168 Ariz. 334, 335, 813 P.2d 315, 316 (1991).

State v. Velasco, 165 Ariz. 480, 799 P.2d 821 (1990).

In State v. Velasco, 165 Ariz. 480, 488–89, 799 P.2d 821, 829–30 (1990), the court held that the United States Supreme Court’s holding in Youngblooddid not change the government’s duty to preserve biological evidence it has seized in a DUI case. The court in Velasco states:

The state points out that subsequent to our decisions in Scalesand Baca, the United States Supreme Court held that the due process clause of the fourteenth amendment does not require the state and its agencies to preserve breath samples of DUI defendants for independent testing. See California v. Trombetta, 467 U.S. 479, 104 S.Ct. 2528, 81 L.Ed.2d 413 (1984). Thus, the state argues, much of the underlying rationale of Scalesand Baca and many of the authorities cited or relied on by those cases are no longer viable. This is even more apparent, the state contends, in view of the United States Supreme Court’s recent decision in Arizona v. Youngblood, 488 U.S. 51, 109 S.Ct. 333, 102 L.Ed.2d 281 (1988), holding that due process requires the prosecution to collect, preserve, and present to the defendant only evidence that has actual and apparent exculpatory value, not evidence that is only potentially exculpatory. Id. at 56 n., 109 S.Ct. at 336 n.

We believe Youngblood is inapposite. That case dealt with the destruction of clothing containing semen stains, and as the Court noted, “unlike in Trombetta, the state did not attempt to make any use of the materials in its own case in chief.” Id., 488 U.S. at 56, 109 S.Ct. at 336.  In the case before us, like Trombetta but unlike Youngblood, the state did use “the materials”—the defendant’s breath and its test results—in its case in chief.  Blood alcohol test results in a § 28–692(B) prosecution are not merely “potentially useful” evidence, they are virtually the entire evidence. A person may not be convicted of a violation of subsection (B) without evidence of chemical analysis of blood, breath, or urine showing a BAC in the proscribed range. State v. Superior Court, 149 Ariz. at 279, 718 P.2d at 181 (1986).

Nor do we believe our cases are necessarily in conflict with TrombettaTrombetta concluded that due process was not violated by the state’s failure to capture and preserve the breath discharged from the Intoxilyzer in the context of the procedure used in California DUI cases.6 We recently held that a similar methodology in Arizona satisfies due process. See State ex rel. Dean v. City Court, 163 Ariz. 510, 789 P.2d 180 (1990) (due process was not violated where defendant was given choice between replicate breath test with no sample saved and blood test at state expense); see also Oshrin, 142 Ariz. at 113, 688 P.2d at 1005.

State v. Velasco, 165 Ariz. 480, 489, 799 P.2d 821, 830 (1990).

What is the remedy?

There are some cases where the destruction of evidence merely justifies an adverse jury instruction.  However, the Arizona Supreme Court has held that a Willits instruction does not adequately protects a Defendant’s rights when he is prejudiced by that loss of evidence or the Defendant can prove the State acted in bad faith.  State v. Schad, 163 Ariz. 411, 416 (1989).  As noted in State v. Rivera, 152 Ariz. 507, 511 (1987):

In incidences where the evidence is no longer available because the state has destroyed the evidence or failed to preserve the evidence the defendant’s due process rights may none the less be protected by giving a Willits instruction to the jury.  However, if the state had destroyed evidenceand the prejudice caused to the defendant is greator the state acted in bad faith or with connivance the charges against the defendant must be dropped or his conviction reversed; a Willits instruction is insufficient to cure the violation of a defendant’s due process right. (emphasis added)

State v. Rivera, 152 Ariz. 507, 511 (1987).

The “bad faith” required for dismissal does not require that the State acted with intent to destroy evidence favorable to the Defendant; rather, within the meaning of the law “bad faith” is a “conscious intentional or malicious failure to preserve evidence.” State v. Youngblood, 173 Ariz. 502, 506 (1993).  

To illustrate, in State v. Hannah (Real Party in Interest Farhang), 120 Ariz. 1, 2 (1978) arson charges against the Defendant were dismissed by the trial court because the State destroyed evidence without testing it for possible exculpatory proof, and the court found that a Willitsinstruction would not otherwise cure the due process violation.  State v. Hannah (Real Party in Interest Farhang), 120 Ariz. 1, 2 (1978).  The order to dismiss was found to be an appropriate remedy on appeal even though the defense in that case had not made a request for production of the evidence until shortly before trial.  

Moreover, in State v. Lopez, 156 Ariz. 573, 574 (1988) the court ruled that dismissal was proper when there is a reasonable possibility that the requested evidence would be favorable and material to the defense.  Lopez, 156 Ariz. 573, 574 (1988). The Lopez court cited Brady v. Maryland in finding that “due process requires the state to produce any information that is material to the issue of defendant’s guilt.”  Lopez, 156 Ariz. at 574.  

In Arizona DUI cases the remedy for the government’s failure to preserve a blood sample is well established.  In Amos v. Bowen, 143 Ariz. 324, 328, 693 P.2d 979, 983 (App. 1984), the Court of Appeals held an “unreasonable or unconstitutional interference” with attempts to secure a blood sample for exculpatory purposes in a DWI prosecution “requires a stay or dismissal of the charge as a remedy.” Amos v. Bowen, 143 Ariz. 324, 328, 693 P.2d 979, 983 (App. 1984).  

Due Process requires a “fair chance” to obtain independent evidence of sobriety. See Smith v. Ganske, 114 Ariz. 515, 517, 562 P.2d 395, 397 (App. 1977).  


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