ALBUQUERQUE, N. M. - Defense attorneys trying to spare convicted murderer John McCluskey from the death penalty showed jurors a scan Wednesday that they say shows "a small defect" in one area of his brain.
Wrapping up the first phase of McCluskey's sentencing trial, the last defense witness, radiologist Mark Depper, testified that scans of McCluskey's brain show a defect in the left cerebellum, an area that is most associated with coordinating movement and balance.
The defense has called several neurological experts over the last week in support of their argument that McCluskey is incapable of controlling his impulses and making reasoned decisions due to brain abnormalities, emotional and physical abuse, and a long history of drug and alcohol abuse.
Prosecutors on Wednesday again pointed to McCluskey's violent criminal past, saying he meets the criteria for the death penalty.
McCluskey was convicted Oct. 7 of first-degree murder in the August 2010 carjacking killings of Linda and Gary Haas. The killings happened just days after McCluskey and two other inmates escaped from an Arizona prison.
Under questioning by prosecutor Greg Fouratt, Depper acknowledged he did not see anything abnormal about the areas of the brain connected with reasoning, planning, perception and emotions.
Experts who testified Tuesday said McCluskey had fewer arteries in his brain and that heavy drinking as a youngster likely affected his development.
"Your brain really doesn't mature from that point on," said defense witness Dr. Alex Stalcup. "The decisions he made weren't adult decisions."
In the first phase of McCluskey's sentencing trial, jurors are weighing whether he is eligible for the death penalty or a life sentence. They are expected to begin deliberating after closing arguments Thursday.
Outside the jury's presence, lead defense attorney Michael Burt raised questions about attempts by prosecutors to introduce evidence that suggested McCluskey might have anti-social personality disorder.
Burt said such a diagnosis would be a "damaging, prejudicial characterization" and beyond the scope of examinations done by experts who testified for the defense.
Prosecutor Mike Warbel argued that defense witnesses have already mentioned other disorders such as post-traumatic stress disorder and attention deficit disorder.
McCluskey was serving 15 years for attempted second-degree murder, aggravated assault and discharge of a firearm when he and two other prisoners escaped from a medium-security prison near Kingman, Ariz., in July 2010 with the help of his cousin and fiancee, Casslyn Welch.
One inmate was quickly captured after a shootout with authorities in Colorado, while McCluskey, Welch and inmate Tracy Province headed to New Mexico. Their escape and ensuing crimes sparked a nationwide manhunt and an Interpol alert.
Testimony showed the trio targeted the Haases at a rest stop near the New Mexico-Texas state line. Within an hour, the Haases were dead. Their charred remains were found among the wreckage of their burned-out travel trailer on a remote ranch in eastern New Mexico.
Province and Welch pleaded guilty last year to charges of carjacking resulting in death, conspiracy, the use of a firearm during a violent crime and other charges. They both said McCluskey was the triggerman.
The victims, who were high school sweethearts and recent retirees from General Motors, were making their 11th summer trip to Colorado when they were killed three days after the prison break.