Jeffery Trevino's attorney is seeking to have his client's second-degree unintentional murder conviction thrown out, claiming an insufficient legal basis for the jury verdict handed down this month.

Trevino was convicted Oct. 2 of killing his wife, Kira Steger, after a two-week trial. His attorney, John Conard, filed a motion Wednesday arguing that Trevino should be acquitted because the injuries to Steger rose to the level of third-degree assault, which does not support the murder conviction.

Minnesota law defines second-degree unintentional murder as an act causing the death of "a human being, without intent to effect the death of any person, while committing or attempting to commit a felony offense other than criminal sexual conduct in the first or second degree with force or violence or a drive-by shooting …"

Conard wrote in his motion that "there is insufficient support for the verdict as a matter of law because assault in the 3rd degree cannot serve as a predicate felony for a felony murder charge."

Assistant Ramsey County attorneys Richard Dusterhoft and Andrew Johnson told jurors at trial that Trevino, 39, killed Steger, 30, because she was having an affair and wanted to leave their marriage.

Steger was last seen alive in public having dinner and bowling with Trevino on Feb. 21 at the Mall of America. Trevino reported her missing to police on Feb. 24, but prosecutors believe Steger was killed within two hours of texting the other man she was seeing shortly before midnight on Feb. 21.

Conard argued at trial that the prosecution had incomplete forensic evidence and that someone involved with marijuana could have killed Steger, whose friend testified that she used the drug recreationally.

Conard wrote in his motion that Steger's broken finger was a third-degree assault that did not support the conviction and that there was no evidence that death resulted from "the other serious injury," a cut above Steger's left eyebrow.

Conard did not address Dusterhoft's assertion at trial that Trevino likely smothered Steger with a pillow that was found in a plastic bag with her DNA and presumptive blood on it.

Ramsey County Medical Examiner Michael McGee testified at trial that Steger's injuries show she was likely smothered by a pillow or hand, in addition to being cut above the eyebrow and having her left index finger snapped.

"Even if he was simply assaulting her by putting a pillow over her face, that pillow became a weapon and he was assaulting her with a weapon," said Joseph Daly, emeritus professor at the Hamline University law school. "And that's a felony."

Conard asked the court to dismiss the charges against Trevino on the last day of testimony, saying that prosecutors hadn't proven their case. The jury acquitted Trevino of second-degree intentional murder.

That move and Conard's latest motion are not unusual, Daly said.

"In some ways, it's boilerplate, meaning you file any single motion you can think of that might convince a judge to give a new trial or to convince an appellate court to grant a new trial," Daly said.

"I would expect him to do that, but the chances of the court granting his request is virtually nil."

In his motion, Conard said he would introduce his argument in court on Nov. 25, the date Trevino is scheduled to be sentenced, or "as soon thereafter" as possible.

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