Las Vegas Review-Journal (Sunday)
Police lab promoted tests despite known errors
At the outset of the 1990s, the Metropolitan Police Department began making thousands of arrests every year using inexpensive test kits meant to detect illegal drugs. Officers simply had to drop suspected cocaine or methamphetamine – taken from someone’s pocket or the floorboards of their car – into a pouch of chemicals and watch for telltale changes in colors. Known as “field tests,” police embraced them as essential in busting drug users and dealers. Local judges became sold on the kits’ usefulness and prosecutors relied on them to quickly secure guilty pleas – hundreds upon hundreds, year after year.
All along, though, police and prosecutors knew the tests were vulnerable to error, and by 2010, the police department’s crime lab wanted to abandon its kits for methamphetamine and cocaine. In a 2014 report that Metro submitted to the U.S. Department of Justice under the terms of a federal grant, the lab detailed how the kits produced false positives. Legal substances sometimes create the same colors as illegal drugs. Officers conducting the tests, lab officials acknowledged, misinterpreted results. New technology was available – and clearly needed to protect against wrongful convictions..
Yet to this day, the kits remain in everyday use in Las Vegas. In 2015, the police department made some 5,000 arrests for drug offenses, and the local courts churned out 4,600 drug convictions, nearly threequarters of them relying on field test results, according to an analysis of police and court data. Indeed, the department has expanded the use of the kits, adding heroin to the list of illegal drugs the tests can be used to detect.
There’s no way to quantify exactly how many times the field tests were wrong or how many innocent people pleaded guilty based on the inaccurate results, or to assess the damage to their lives.
To be sure, most field tests are accurate and most drug defendants who take plea deals are guilty. But — just as certainly — there have been some number of convictions based on false positives. How many? The department maintains it has never established an error rate. The department destroys samples after pleas are entered and does not track how many of its field test results are re-checked. Drug arrest and lab testing data show the number could be as low as 10 percent.
What is clear is that even as they continue to employ field tests to secure arrests and gain convictions, neither the Las Vegas Metropolitan Police Department nor the Clark County district attorney’s office has informed local judges of the long-standing knowledge of their unreliability. And neither has taken any additional steps to prevent mistakes.
Informed recently of the findings reported to the Justice Department, Joe Bonaventure, chief judge of the Las Vegas Justice Court, expressed concern about the flaws but did not say whether he plans to change his court’s regard for the tests.
“These are tests that have been accepted for years,” said Bonaventure, who became a judge in 2004. “They’re not being challenged.”
Kim Murga, the director of the Las Vegas police crime lab, said the department still wants to stop using chemical field tests in arrests for methamphetamine and cocaine. “We don’t turn a blind eye” to the risk of false positives, Murga said. But she acknowledged that the lab had not tried to more effectively eliminate errors.
In 2014, the same year Metro’s report to the DOJ detailed misgivings about the reliability of field tests, prosecutors in Houston identified more than 300 cases in which innocent people took plea deals largely based on field test results that proved wrong. Unlike in Las Vegas, Houston’s lab hung on to evidence even after defendants pleaded guilty. Lab tests later proved that the alleged drugs were not controlled substances. By that time, though, many people had spent time in jail or prison. Some were saddled for years with felony convictions that devastated their lives.
The district attorney’s office in Harris County, the jurisdiction where Houston is, no longer accepts guilty pleas based on field tests. Drug evidence must be confirmed