It could take a pool of as many as 800 prospective jurors to find a panel of 12 and a few alternates, but Ada County prosecutors say they are confident in their case against Lacey Sivak in the shooting and stabbing death of Dixie Wilson.

Sivak was supposed to get his sentencing hearing this month, at which prosecutors would try to convince a jury that Wilson's slaying was done with such utter disregard for human life that Sivak himself should be put to death.

That has all been delayed until October, at the request of Sivak's attorneys. Testimony in the resentencing hearing, which will actually be much like a trial, is set to begin on Oct. 16 in front of 4th District Judge Ronald Wilper.

Court records do not indicate what witnesses prosecutors plan to call, but records show that they have sent several items of clothing to a lab for DNA processing.

Court records obtained by the Idaho Statesman show that Sivak's attorneys are preparing a mitigation defense that appears to focus on Sivak's mental health.

The defense will call two expert witnesses, Boise psychologist Craig Beaver and San Francisco psychiatrist Pablo Stewart, who have testified in several previous Ada County death-penalty cases. Sivak's attorneys also have asked for MRI and PET scans of his brain.

GARDEN CITY MURDER

The guilt of Sivak, who has spent more time on Idaho's death row than anyone, is not in question.

In 2011, the 9th Circuit Court of Appeals determined that Sivak's conviction for first-degree murder was appropriate.

Sivak's victim, a former co-worker, was shot at least five times in the head and face and stabbed about 20 times in the head, neck and shoulder at the Baird gas station in Garden City. The 30-year-old mother of three also was sexually molested.

Sivak has maintained that he witnessed but didn't commit the killing. He had been fired from a job at the same station six weeks earlier, in part because he was unable to work with Wilson, according to Statesman files.

Sivak's co-defendant, Randall Bainbridge, is serving a life sentence.

Sivak filed dozens of appeals and petitions. He was briefly scheduled to die by firing squad on Jan. 31, 1984, but the Idaho Supreme Court granted a stay.

In 20111, the 9th Circuit judges said that Sivak's death sentence might have been different if Ada County prosecutors had not knowingly presented testimony from:

• An inmate who lied that he didn't have expectations of receiving preferential treatment in return for his testimony.

• An inmate who admitted he was a habitual liar.

AGGRAVATING VS. MITIGATING FACTORS

To impose the death penalty, a jury must unanimously find that aggravating factors - such as whether Sivak showed an utter disregard for human life, has a propensity to commit murder and continues to be a threat to society - outweigh the mitigating factors offered by the defense.

Mitigation is not as strictly defined. Defense attorneys may offer evidence about anything they say might have contributed to what happened. Commonly used mitigating factors include mental health issues or a history of childhood trauma, including mental, physical and sexual abuse.

At Sivak's original sentencing hearing, his mother and sister testified that Sivak's alcoholic father often beat him as a child. His mother testified that he was a hyperactive child, and a medical expert testified about the link between attention deficit hyperactivity disorder and criminal behavior.

It is unclear whether Bainbridge will testify. The Idaho Supreme Court overturned Bainbridge's original conviction because police used hypnosis to enhance the testimony of key witnesses. Bainbridge was retried and found guilty of murder for a second time in the mid-80s.

DEATH PENALTY IN ADA COUNTY

The Idaho Legislature changed the death penalty law in 2003 to have juries, not judges, make that ultimate decision. So far that's happened only in Ada County, where juries have called for the execution of three killers: Erick Hall, Azad Abdullah and Darrell Payne. In two other Ada County death penalty cases, juries spared the lives of convicted killers Jason McDermott and Ignacio Sanchez.

It's in such cases that testimony of experts such as Pablo Stewart comes into play.

Stewart testified as an expert for Sanchez, who beat a 2-year-old girl to death in 2003. He told the jury that Sanchez suffered from disorders including depression and "methamphetamine-enhanced" psychosis at the time of the murder.

Stewart interviewed Sanchez twice and examined his medical, school and juvenile detention records. He told the jury that Sanchez suffered post-traumatic stress syndrome from being physically abused as a child, attention deficit disorder and "cognitive impairment" - or troubled thinking.

The jury in the case was unable to come to a unanimous agreement on the death penalty.

Patrick Orr: 377-6219, Twitter: @IDS_Orr