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Psychology Expert Witnesses Testify in Colorado Murder Sentencing Trial

A Colorado man convicted of murdering five people outside of a bar avoided the death penalty when jurors found sufficient mitigating factors to believe he deserved jail time instead of execution.  In part, the jury was influenced by psychology expert witnesses presented by the defense during the sentencing phase who testified that the defendant’s history of childhood abuse warped his worldview and decision-making.

Colorado Man Convicted of Murder for Stabbing Death of Five People

In mid-August a Colorado jury found Dexter Lewis guilty for murdering 5 people outside of a Denver bar in 2012.  Lewis was convicted of stabbing his victims multiple times during what prosecutors called an act of rage and savagery.  Lewis allegedly went to the bar with intent to rob it, but instead acted violently against the bar’s owner and four patrons before lighting the building on fire with their bodies inside.    Throughout the trial, prosecutors showed grisly pictures of the scene to paint Lewis as a vicious and remorseless killer which convinced jurors that he was guilty of the crimes committed.

After the verdict was announced, jurors prepared to pass judgment in the second phase of the trial which would determine an appropriate sentence.  In an effort to reinforce the extreme nature of the crime, prosecutors again highlighted the visual evidence taken from the scene as they argued Lewis deserved to be put to death.  Defense attorneys for Lewis countered by telling jurors about the defendant’s history of suffering abuse at the hands of his mother and step-father in the gang influenced environment where he grew up.  Lewis’s attorneys called two psychology expert witnesses to use his challenged background as a mitigating factor that would help him avoid execution.

Psychology Expert Witness Testifies about Effect of Childhood Abuse

During the sentencing phase for the Dexter Lewis murder trial, prosecutors attempted to convince jurors that the brutality of the defendant’s actions was severe enough to warrant the death penalty.  Defense attorneys for Lewis countered that the abuse the defendant suffered during his childhood effected his brain development and altered the way he perceived the nature of his actions.  Prosecutors objected to the use of psychology expert witnesses by arguing it was up to the jury to identify mitigating factors, but both of Lewis’s experts took the stand during his sentencing phase.

First to testify for Lewis was Dr. Bruce Perry, a psychiatrist who is an expert on the effects of childhood trauma on development.  During his testimony, Dr. Perry spoke about how abuse, particularly abuse by a parent, alters the way children develop and can explain why they would grow into violent adults.  Perry, who founded the Child Trauma Academy in Houston, Texas, told jurors that abuse during the period when children form relationships that help dictate how they view the world leaves executive function of the brain impaired.  Dr. Perry concluded his expert testimony by telling jurors that impaired development can cause children to grow up without impulse control or the ability to regulate emotions in stressful situations.

Although Dr. Perry did not work with Lewis personally, his testimony showed jurors that people who suffer the abuse and neglect that Lewis suffered could become violent due to lack of brain development.  To directly connect Lewis’s condition with Perry’s testimony, defense attorneys wrapped up their case by calling a clinical psychologist who analyzed the defendant’s mental state.

Clinical Psychologist Expert Witness Takes Stand for Dexter Lewis

Mark Cunningham, a clinical psychology expert witness, took the stand last as defense attorneys for Dexter Lewis argued the defendant did not deserve the death penalty.  Cunningham echoed the expert testimony from Dr. Perry by pointing to the long term effects that regular abuse has on children, and showed jurors that the sustained and severe abuse that Lewis suffered throughout his childhood impaired his ability to make reasonable decisions and control violent impulses.  Although Cunningham was not permitted to testify about the content of his interviews with the defendant, he told jurors that Lewis’s history of physical and emotional abuse would have a severe impact on the developmental process.

Ultimately the jury agreed that Dexter Lewis deserved leniency to avoid the death penalty, assuring that the defendant will instead spend the rest of his life in prison.  Use of psychology expert witnesses during a capital murder sentencing phase has become more commonplace, and attorneys for Dexter Lewis demonstrated that helping jurors understand the negative effects of childhood trauma can convince a jury to opt for life in prison instead of execution.