The U.S. Supreme Court recently decided on a landmark ruling that has significant bearing on all criminal defense cases across the United States. The ruling states that when trying to prove a criminal fact, the individual who performed the test to determine the fact must also be the one to testify in Court, and other experts or substitutes may not be used. This ruling also applies to law enforcement officers who use radar guns to determine a driver’s speed.

For example, what this means in a DUI test is that if a person arrested for suspicion of DUI fails a breathalyzer test, the police officer who administered the breathalyzer must be the one to testify in Court. This new ruling would exclude anyone else from testifying in court on the matter, whether it is a colleague, a witness to the test administration, or any other individual.

According to the Sixth Amendment, a person has the right “to be confronted with the witnesses against him.” The Supreme Court interpreted this clause to mean that while testimonies of witnesses received outside the courtroom may be used during criminal proceedings, actual evidence such as lab reports and breathalyzer results, as used in the example above, must be presented by the person who administered the test in the first place. The only exception to this rule is if both the prosecution and the defense agree beforehand to allow some other person to testify in place of the test administrator.

Source: http://www.upi.com/Top_News/US/2011/06/23/Supreme-Court-Test-operator-must-testify-at-trial/UPI-26861308843865/#ixzz1QEvpAa4m