Polygraphs are not admissible in Texas criminal courts.
Under the Texas Rules of Evidence, courts have found that polygraphs lack sufficient scientific reliability. So why should an accused person still take one? As any good criminal practitioner knows, the polygraph is an important tool at the right time and place.
The Irony of Inadmissibility Every jurisdiction in Texas uses polygraphs. Police departments use them as part of criminal investigations. Probation departments use them to determine if a person is following probation conditions and to investigate a person’s criminal history (especially in cases related to sex offenses). Even some district attorney’s offices use them to investigate charges and meet protocols for conviction integrity analysis (such as innocence’s claims). Most criminal justice practitioners trust our own polygraphs and distrust the other side’s polygraphs—sometimes for very good reasons. So, if polygraphs are inadmissible and not always trusted, why bother with them?
The Usefulness of Polygraphs Polygraphs can be useful in two primary ways:
1) they can be effective in non-trial settings, and 2) they can produce more just results by providing law enforcement and prosecutors an additional perspective. There are multiple opportunities to use a polygraph result before trial. Over the years, we have used polygraphs to keep police officers from filing a case, to compel a district attorney’s office to reject a case, or to convince a grand jury to no-bill a case. The polygraph itself is never dispositive, but it can be used very effectively in the right setting. In today’s world many allegations are based on one person’s word. We see this regularly in family violence, sexual assault, and child abuse allegations. Usually with these one-person allegations, the police file the charge and the district attorney’s office pursues prosecution. And there are good reasons for this. As a society, we want the criminal justice system to take such allegations seriously. Sadly, we know we have failed falsely accused
victims far too often in the past. But to criminally charge someone based on another’s word puts immense power behind an uncorroborated and unproven accusation, and not all accusations are true. A polygraph gives a black-and-white result that expands law enforcement’s capacity to see the other side.
When and How to Polygraph If you choose to have a client take a polygraph. The details matter. Here are a few important tips: Always hire a professional polygrapher, and never take a polygraph given by a law enforcement officer. As with most professions, you do not hire an electrician to do your plumbing and you do not use a generalist to do a specialist’s job. Law enforcement officers investigate crimes and use polygraphy as a tool to that end. You want an expert who lives and breathes polygraphy and knows the latest research and techniques. Choose a polygrapher who is well known in your jurisdiction. As mentioned above, police departments, probation departments, and district attorney’s offices also use polygraphers. If you use a polygrapher who is known to the other side, your result will carry more weight. Hire the polygrapher for your client and make sure everyone knows that this polygraph is protected by the work product and attorney/client privileges. This underscores another reason why a polygraph administered by law enforcement is a bad idea. Polygraphs are not a perfect tool (and clients are not perfect either). Sometimes a report comes back inconclusive or negative for a client—this is especially true when using a highly reputable polygrapher. So make sure you control who sees the polygraph result. As the criminal attorney, have the polygraph result delivered only to you. A criminals attorney is not required to turn over anything in discovery. This is not always true for results in the possession of a client or civil attorney. If your client must take a polygraph administered by law enforcement, give preference to a federal practitioner over a state or local law enforcement polygrapher. Without getting into the weeds too much, federal law enforcement practitioners are generally more up to date than local and state practitioners. For more explanation, find a comfortable chair and ask your favorite private polygrapher to explain the difference between directed lie and probable lie tests.
Looking to the Future The science behind polygraphy is improving all the time. Many jurisdictions now allow polygraph results in certain situations, and federal courts are more open to polygraphs than Texas state courts. Change is slow, but we are seeing progress.
