Two suspects in the murder of a University of Kentucky student have presented expert witness testimony in an effort to avoid the possibility of a death sentence. Attorneys representing the young men have called a trained neuro-psychologist to testify in support of a motion which argues the defendants’ brains were not fully developed at the time of the murder. The same tactic was famously used unsuccessfully in the Boston Marathon bomber trial of Dzhokhar Tsarnaev, who was sentenced to death in June of 2015 for his role in the attack.
Kentucky Men Face Murder Charges in Student’s Death
Efrain Diaz and Justin Smith are set to begin trial for the murder of 22-year-old University of Kentucky Student Jonathan Krueger during a robbery in 2015. Diaz, Smith, and another man allegedly attempted to rob Krueger before the incident turned fatal when shots were fired after the victim and a friend resisted. Police claim that all three young men have ties to a street gang known as the Almighty Ambrose, and claim that they were all armed at the time of the robbery. Although statements made to the policy following their arrest have been ruled inadmissible because the officers violated the suspect’s rights to remain silent and request an attorney, prosecutors believe they have enough evidence to pursue murder charges.
The third defendant, who was 17 at the time of the murder, is not eligible to receive the death penalty due to his age, but Diaz (20 at the time of the killing) and Smith (18 at the time) can both be charged with capital murder and be sentenced to death should they be found guilty. In an effort to avoid the death penalty, attorneys representing the two capital defendants have argued that their brains were not properly developed at the time of the killing. To bolster their argument, the defense has called on a psychology expert in brain development.
Brain Development Psychologist Testifies in Kentucky Trial
During a pretrial motion hearing requesting a ruling that the defendants are ineligible for the death penalty due to brain underdevelopment, attorneys for Diaz and Smith called on Laurence Steinberg, a psychologist at Temple University who specializes in brain development. Dr. Steinberg testified only in front of the judge, who will make the final determination of whether or not Diaz and Smith are sufficiently competent to be tried in a capital case. According to Kentucky law, anyone who is older than 17 at the time they commit a crime can face capital charges, however, attorneys for Diaz and Smith argue that the advances in brain development psychology have shown that the judge should consider more than simply the age of the defendants.
Dr. Steinberg told the court that the brains of 18 to 20-year-olds are typically closer in developmental maturity to teenagers than to adults, but conceded that he was speaking in generalities because there is not a reliable way to measure individual brain maturity levels. Still, Steinberg testified that over the last decade, advances in brain research have indicated that the type of maturation previously assumed to occur between the ages of 10 and 18 actually continues well into the early-to-mid-20s, which suggests that assumptions that the law carries about the mental competence of 18-to-20-year-olds is based on a flawed understanding of human development.
Steinberg explained that the type of impetuous decision-making heavily influenced by peer pressure and other negative outside influences which we typically associate with teenagers is, in fact, highly influential in brains of 20-year-olds as well. Although the legal system, led by a 2005 Supreme Court decision banning the death penalty on anyone younger than 18, has consistently drawn a bright line at 18, Steinberg noted that research suggests this conclusion is incongruent with biological reality. During a cross-examination period, the lead prosecutor in the case had Steinberg admit that 18-to-20-year-olds do know the difference between right and wrong, and that he was personally against the death penalty.
Judicial Ruling Could Challenge Kentucky Death Penalty Statute
After hearing Steinberg’s testimony and reviewing an expert witness report on brain development that he prepared for the court, the trial judge will determine if Diaz and Smith are ineligible for the death penalty despite being old enough at the time of the incident. Kentucky law, which is similar to other death penalty state laws, sets the capital sentence bar at 18, but legislators likely did so without substantial contribution from the brain development science community. Should the trial judge agree with defense attorneys and Dr. Steinberg, he will upset the apple cart and open the door for an exception to Kentucky’s law which was not included by the state legislature.
Ultimately, it is likely a tough battle for the defendants to fight as courts have shown reluctance to turn to brain development science for information to change assumptions made by the criminal justice system. Dzhokhar Tsarnaev, convicted for his role in the Boston Marathon attacks, attempted to use a similar tactic to avoid the death penalty in federal court two years ago, but was unsuccessful because jurors ultimately found that the ability to understand right from wrong was sufficient to justify a capital sentence. This underlying argument, coupled with historic resistance by judges to defy death penalty parameters set in law, suggests it is improbable Diaz and Smith will be found ineligible for the death penalty, but capital sentencing law in Kentucky and across the country could face a stiff challenge should the judge side with the defense.