COEUR d’ALENE — Prosecutors and an expert defense witness who took the stand for six hours Thursday clashed over scientific evidence that the state called questionable, but the defense used to show Jonathan D. Renfro suffers from brain abnormalities.

The evidence was used by the defense to enforce earlier expert testimony that Renfro’s dysfunctions played a significant role in the defendant’s shooting Coeur d’Alene Police Sgt. Greg Moore to death two years ago.

Renfro, 29, who was convicted earlier of murdering Moore, could receive the death penalty if jurors after considering evidence rendered in this final phase of his trial that began Sept. 11, agree that it is warranted.

Earlier this week in Coeur d’Alene’s First District Court, Dr. Mark Cunningham, a Seattle clinical forensic psychologist hired by Renfro’s attorneys, for two days listed for the jury an array of adverse or impairing factors that disposed the defendant to a life of crime, that culminated in the May 2015 fatal shooting of Moore.

Cunningham argued that the defendant’s hyperactivity and recklessness brought on by ADHD, parental neglect, coupled with a series of head injuries, a history of alcohol abuse among relatives and his own drug and alcohol abuse from an early age, lousy peers, serial impulsivity and learning disorders were symptomatic of neurological dysfunction.

Deputy prosecutor David Robins boiled it down to something else.

“Did he have a choice?” Robins repeatedly asked.

Renfro did make a choice when he shot Moore, Cunningham said.

“The point of this is not that he had a choice,” he said. “But what’s been loaded into his system, what’s he’s making the choices with.”

Thursday’s expert witness, psychologist Richard Adler, further developed the argument that Renfro suffered from a brain disorder evidenced by a series of photograph-like images of Renfro’s brain that showed points of trauma. He pointed out degeneration of white matter responsible for transmitting information from the front to the back of the brain, and shrunken portions on one side of the brain that were not symmetrical with their mirror images on the other side.

Physical evidence coinciding with the findings include Renfro’s choppy speech patterns and mannerisms as well inabilities to make cognitive connections, and his lack of social skills, Adler said.

Defense attorney Jay Logsdon asked if the images were obtained through a discredited method, one that has “been attacked as junk science?”

The method, called QEEG, for quantitative electroencephalogram, which uses electrical patterns that show electrical activity inside the brain’s cortex to determine impairment, was attacked in an article in 1997. The article’s criticism still stands today, Adler said.

Throughout the morning and into the afternoon, Adler reiterated findings, linking them to the defendant’s actions, and dovetailing them into other test results, psychological and cognitive, that have been conducted while Renfro has been incarcerated in the Kootenai County Jail.

Since Renfro has been prescribed Seroquel, an antipsychotic medicine often used to treat bipolar and depressive disorders, many of the symptoms have been relieved, and the defendant experiences something closer to normal brain functioning, Adler said.

The final phase of the trial to determine if Renfro should be put to death, resumes today at 9 a.m. in Courtroom 1 of the Old Kootenai County Courthouse.