A Lewiston sheriff’s deputy whose murder conviction in the strangling death of his ex-wife six years ago was overturned by the Idaho Supreme Court appeared Wednesday for his retrial in Coeur d’Alene’s First District Court as part of a venue change.

Joseph A. Thomas Jr. was convicted in 2011 of strangling his ex-wife, Beth Irby-Thomas, with a belt after the couple had sex in her Lewiston home. He was sentenced to more than 25 years in prison.

But the Idaho Supreme Court overturned the conviction because the judge in the original trial had prohibited the defendant from using evidence that may have proven his innocence.

According to prosecutors, Thomas had spent an evening with his ex-wife, and the couple had sex at her Lewiston home where, prosecutors say, Thomas strangled the 25-year-old woman with his belt.

After the incident, according to prosecutors, Thomas drove to the house of his friend and co-worker, Guy Arnzen, a county deputy, and confessed to the killing. Arnzen called police.

Thomas, however, denied killing Irby-Thomas, arguing instead that his ex-wife enjoyed being choked while having sex, a practice called autoerotic asphyxiation. He said his ex-wife had inadvertently strangled herself to death while having sex alone after he left her house.

Thomas was convicted in Lewiston of first-degree murder, but a Second District judge prohibited evidence involving autoerotic asphyxiation. The Idaho Supreme Court, on appeal, ruled the evidence should have been allowed and overturned the 2011 conviction, sending the highly publicized murder case back to Lewiston for a retrial.

A survey earlier this year found that seating an unbiased jury in Nez Perce County was unlikely, and the retrial was moved to Coeur d’Alene. Thomas was moved from prison to Nez Perce County Jail pending this trial and then shipped to Kootenai County jail when the trial’s venue was changed.

The second trial, which began Wednesday in the Juvenile Justice Center — the old federal courthouse downtown Coeur d’Alene — is not without challenges.

Prosecutors, in an effort not to prejudice the jury, may not reference Thomas’ earlier conviction, and Coeur d’Alene defense attorney Anne Taylor, who represents Thomas along with co-counsel Dennis Reuter, will not have the opportunity to cross examine Arnzen, the key witness who died three years ago.

A partially redacted recording of Arnzen’s testimony from the first trial will be played for the jury and some segments will be read aloud.

In opening statements Wednesday, Taylor said her client was in love with his ex-wife, that the couple jointly raised their two children and got along well together.

Taylor said jurors will be shown evidence of Irby-Thomas’ proclivity for autoerotic asphyxiation. When performed alone, Taylor said, no one knows about it.

“The public only finds out when something goes terribly, terribly wrong,” she said.

But prosecutors Justin Coleman of Lewiston and Casey J. Hemmer of the attorney general’s office said the couple’s relationship was volatile, that Irby-Thomas had no history of enjoying being choked while having sex, and that the defendant’s version of the incident has changed over the years.

“He killed Irby-Thomas by strangling her with his own belt,” Hemmer told the jury Wednesday.

Witnesses in the two-week trial include psychologists, medical professionals, police and family members. Closing arguments are scheduled June 13.