Amy Senser's homicide convictions should be overturned because prosecutors failed to prove she knew she had struck and killed a Minneapolis chef before leaving the crash, her attorney argued in an appeal filed Wednesday.

In a 45-page brief filed with the Minnesota Court of Appeals, attorney Eric Nelson expanded on a motion filed last summer, citing a dozen judicial missteps he said sealed his client's fate.

"Ms. Senser's case underwent a series of unusual occurrences and prejudicial rulings that strongly contributed to the jury's verdicts of conviction," he wrote.

In May, a jury convicted Senser of striking and killing Anousone Phanthavong in August 2011 as he put gas in his stalled car on an I-94 exit ramp. She was sentenced in July to 3 1/2 years at the Minnesota women's prison in Shakopee. At the sentencing and in post trial hearings, Hennepin County District Judge Dan Mabley publicly doubted the candor of Senser's testimony and her willingness to accept responsibility for Phanthavong's death.

The headline-grabbing trial of Amy Senser, the wife of former Vikings player and restaurateur Joe Senser, capped eight months of media scrutiny and public speculation over the degree to which Senser would be held accountable for a series of events that left two families devastated.

Charles Laszewski, a spokesman for the Hennepin County attorney's office, declined to comment, adding that his office had received Wednesday's brief very late in the day and had not yet had time to review it. Prosecutors have 45 days to file a response.

Nelson also had no comment on the appeal.

In the brief, however, he outlined three areas of argument:

• There wasn't enough evidence to support the convictions, specifically any proof that Senser had actual knowledge that the accident involved bodily injury or death of an individual.

• The trial judge made legal mistakes.

• The trial judge committed abuses of discretion that affected the jury's decision.

Nelson argued that the trial court failed to sequester the jury during the entire proceedings and argued that the trial court abused its discretion in suppressing evidence regarding Phanthavong's toxicology reports.

A toxicology report from Phanthavong's autopsy showed a high level of cocaine in his system.

In addition, Nelson wrote, the trial court should have allowed defense witnesses to support Senser.

Jury's note at issue

The trial court abused its discretion in failing to disclose a jury's note to Senser, Nelson argued. "In Ms. Senser's case, the jurors sent a note to the Trial Court on the same day the verdict was announced," he wrote in the brief.

"The issue presented by this note, the knowledge requirement of the criminal vehicular homicide law, is central to the case and the jury's determination of guilt. ... Had the jury communication been disclosed, the parties would have had an opportunity to identify potential confusion amongst jurors during their deliberations and recognize the extent of the error in the jury instructions. This opportunity was never presented, as the contents of the note were not disclosed until days after the reading of the verdict."

Phanthavong, 38, a chef at True Thai restaurant in Minneapolis, was putting gas in his stalled car on Aug. 23, 2011, when he was struck and killed.

Senser, 46, left the scene and admitted to being the driver more than a week later, claiming through her attorney and on the witness stand that she did not know she had hit a person with her vehicle that night.

The jury convicted her on two counts of criminal vehicular homicide. At sentencing, she expressed remorse and Nelson asked for leniency, but the judge said a stiff sentence was in order because she had yet to accept responsibility for her actions.

Last summer, Nelson asked that Senser be released from prison pending appeal.

Mabley rejected Senser's release, saying that freeing her could call into question whether she would show up for later court appearances or otherwise influence the case.

Phanthavong's family had settled a wrongful-death lawsuit with the Sensers before the trial began.

Staff writer Abby Simons contributed to this report.

Allie Shah • 612-673-4488