Sometimes, all it takes is an accusation. If you’re accused of a serious crime, you may be assigned bail that you can’t afford. If you can’t afford bail, you could be stuck in jail for days or months. You could lose your job, your housing, your child custody rights. You might decide just to plead guilty and get it over with, especially if the prosecution offers you a deal.
But what if you know you’re innocent? For example, what if a police officer told you that a white powder in your car was cocaine but you knew that it was laundry detergent? There could be any number of explanations, but the field tests cops use to gauge whether unknown substances are illegal can easily be wrong.
In fact, in 2016 the nonprofit newsroom ProPublica found that untold numbers of people were being put in the position of having to decide whether to plead guilty based on a $2 drug test that hasn’t been updated in decades. And, it’s often wrong. The test for cocaine commonly produces false positives when used on common substances like laundry detergent.
Recently, five people were exonerated in Las Vegas after these preliminary field tests were found to have been wrong. All five people had been convicted of possessing small amounts of cocaine. The field test came up positive for cocaine, but the official test at the crime lab showed that the substances were not cocaine, or indeed anything illegal.
Unreliable drug tests are still used for convenience
According to ProPublica, the $2 drug tests police use in the field are highly unreliable. Multiple studies have found that, while they may be good enough to establish probable cause, they are not good enough to prove the presence of illegal drugs to a courtroom standard.
Yet although the field tests aren’t admissible in court, they still result in convictions. This is because people are put under tremendous pressure to plead guilty when a police officer claims to have found illegal drugs in their possession. And, when there is a guilty plea, the drugs are typically not sent for further testing at the crime lab. Instead, the sample is usually destroyed.
Some officers don’t want to use the current field tests, as they produce false positives far more often than false negatives. But when Las Vegas’s crime lab decided to abandon their use, they received pushback.
The field drug tests are easy to use, and they do produce results. They give the officers something they can use in the field that will get them probable cause to arrest.
Yet they’re inaccurate enough that even the manufacturers doubt their use. The Safariland Group, which produces kits for Las Vegas, has said that “field tests are specifically not intended to be used as a factor in the decision to prosecute or convict a suspect.”
What are they specifically intended to do?