In California drug cases, the prosecution will often offer chemical reagent test results as ultimate proof of the existence of a controlled substance for the purpose of obtaining an indictment in a Grand Jury proceeding. Until this week, there has been no published California case that has addressed a scientific challenge to the validity of color drug tests. As a criminal defense attorney who specializes in state and federal drug crimes, I understand that police officers often overstate the reliability of color drug test results in Grand Jury proceedings to obtain an indictment. This type of prejudice to a defendant’s due process rights to a fair Grand Jury probable cause determination is difficult to remedy. As a result, indictments are commonly filed in California drug cases where the scientific evidence showing that a substance is an illegal drug is shaky, and certainly insufficient to prove guilt beyond a reasonable doubt.
This week, the Supreme Court of California ruled in People v. Chacon that a Brady violation occurred when the government did not present known information about the unreliability of the Narcotics Identification Kit (NIK), a commonly used color drug test, to the Grand Jury. Specifically, the government failed to present information that NIK kits have in many instances produced false positive results for drugs to the Grand Jury. One officer in that proceeding testified, wrongly, that the NIK test is “100% accurate.” Broadly speaking, the Chacon case discusses the unreliability of the NIK, which police routinely use in field tests to determine if substances are drugs. Although Chacon is a state court decision, federal defense lawyers should apply the findings in this decision to their federal drug cases when a color drug test is used.
A scientifically reliable analytical testing technique should ideally have a high probability of a “true” result, and minimize the probability of a false positive. The Court in Chacon found that the NIK field color tests are not specific because they fail to discriminate between controlled substances and other compounds. As with all color testing that are used for drug identification, it is not uncommon for there to be a false positive. Limitations with color tests include: (1) they are not specific; (2) the possibility of using too much sample, thereby overwhelming the chemical reagent; and (3) contribution to the color change from other components within he sample. For instance, opium, black tar heroin, and samples containing dyes can produce problematic color test results.
The court, in compliance with its gatekeeping role under Sargon, is required to exclude invalid and unreliable expert opinion. In short, the gatekeeper’s role is to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field. The Court in Chacon found that the NIK colorimetric test or any similar color test does not meet the admissibility requirements of Sargon.
Chacon is a very helpful tool for the defense. State and federal defense lawyers should be extra diligent to pursue discovery regarding the reliability of color drug tests used in the field. Those results can help form the basis of suppression motions, including to challenge warrant applications that rely on those field test results to establish probable cause.