When scientific evidence is introduced in criminal cases, not all such evidence is accurate. Machines make mistakes, and it is important that experienced professionals analyze any evidence before it can be used against a suspect. Defendants in criminal trials have the right to be skeptical of all evidence brought against them, and to analyze and dispute any such evidence.
The Supreme Court of the United States recently upheld this truth of the criminal justice system. The case stemmed from a DWI arrest made in New Mexico. The driver had been involved in a car accident and was under suspicion for drinking and driving. He took a blood test, and his blood was sent to the state forensics laboratory. According to the testing at the lab, his blood alcohol level was allegedly over the legal limit.
The driver fought the charges against him and pled not guilty. At trial, the technician was unavailable to testify. Prosecutors tried to introduce the technician’s written report, along with the testimony of another technician who also worked in the lab. The second technician did not work on the man’s case. The state argued that the technician merely copies the print-out from the machine, but does not otherwise analyze the data, so his testimony is not necessary.
The Supreme Court disagreed explaining that under the Sixth Amendment to the Constitution of the United States, people who are accused of crimes have the right to confront and cross-examine their accuser at trial. They further said that blood alcohol test findings are not necessarily conclusive, as machines are not always accurate and human error does occur.
In fact, a Colorado forensic laboratory was responsible for more than 200 erroneous blood-alcohol readings during a three-year period. As a result, several Colorado criminal prosecutions for drinking and driving have been dismissed because of faulty blood-alcohol results.
This is a very important case for people who face DWI charges in Colorado and across the country. It sets the standard for what is considered reliable scientific evidence. All scientific evidence must be supported by more than simply a machine reading. An analyst must understand the testing procedure and testify in court about its accuracy.
Source: examiner.com, “Supreme Court: machine print out not admissible evidence without human testimony,” Charlie Rosenberg, 23 June 2011