Thank you for the opportunity to assist you.
Q) Field test results are presumptive positive, what does this mean
Field testing of drugs is not the same as a lab analysis. Field tests are done with a chemical reagent. I don't pretend to be a chemist, but essentially various chemical agents react differently with certain substances. The reaction produces a color reaction, which indicates that the substance is, in fact, whatever is being tested. The "presumed positive" means that there is enough evidence for probable cause purposes, which is what is required for arrest.
The substance should still be sent to a laboratory for analysis via gas chromatography
. That sort of testing is usually, but not always, much more exact in identifying what a substance is or is not.
Q) How much material is required for a nark filed test kit #8 in order to have the results be valid
I cannot find a reliable answer to this. Very little, I think, is the best answer. Even if the field test was wrong, but the state lab test comes back as being positive for marijuana, you could still be prosecuted. But, I agree, 0.1 g of marijuana (that's 0.00352 ounces of weed, BTW) is an awfully small amount to test.
Q) How do I get an attorney to challenge this
Possession of less than 20 grams (about 3/4 of an ounce) of marijuana in Florida is a misdemeanor. Since it carries possible jail time (up to one year), you are entitled to a court appointed attorney if you cannot afford one. Otherwise, you can hire any attorney you want. If you do not know a criminal defense attorney, try the Florida State Bar attorney referral service
Q) Is this evidence something that has to be given to the defense
I'm not sure what you mean by "this evidence." The substance should be sent to the state lab and tested there. The test results should be given to you or your attorney.
Q) How does the attorney challenge the truthfulness of the officers statements
By talking to you, to the prosecutor, to the police officer (if he or she will talk before trial), by filing a discovery motion and a demand for exculpatory evidence, and by cross-examining the heck out of the officer at trial. Then it's up to the judge or jury who hears the case whether or not they believe the officer's testimony when he or she testifies about the investigation and alleged discovery of this amazing amount of weed that you possessed. (Sarcasm, obviously.)
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