Krystal Tresler was sentenced to 20 years in the Missouri Department of Corrections for the October 2013 robbery and murder of Adrienne Arnett.

The fourth defendant charged with the robbery and murder of a Hannibal convenience store employee received a 20-year prison sentence in Ralls County Circuit Court, after a jury found her guilty of the crimes in March.

Krystal Tresler, 28, of Hannibal, had requested an acquittal or retrial after a Ralls County jury found her guilty in the October 2013 murder of Adrienne Arnett in March. Both were denied Wednesday by Judge David C. Mobley.

Tresler appeared in person with defense attorneys Brian Sinclair and Therese Marchlewski. Assistant Attorney General Gregory M. Goodwin and Ashley Turner, with the Attorney General’s office, represented the prosecution.

Mobley heard the details of the motion and reviewed Tresler's Sentencing Assessment Report from the Department of Corrections before determining if Tresler's 10-year sentences would run concurrently for a total prison term of 10 years, or consecutively for a total of 20 years.

Sinclair argued for a retrial because he said the state did not provide enough evidence.

But Goodwin, who was assigned to the case through the state attorney general's office, said “there was sufficient evidence” in the case against Tresler. He said the testimony by Gary Wiltermood III — another convicted murderer from the same case — provided additional evidence for a conviction, because he testified “everybody in the van was going to get something” from the robbery.

Sinclair's motion for dismissal hinged on a letter from then-Marion County Prosecuting Attorney Thomas Redington, which mentioned Tresler's testimony against co-defendants Michael Studer and Wiltermood in 2013. Although no written deal had been struck, he said Tresler's attorney believed she would not be charged if she testified against Studer and Wiltermood.

Goodwin countered that no plea deal or immunity was granted to Tresler in exchange for that testimony. Tresler, Cuda Dodd and Amanda Lehenbauer were arrested and charged with robbery and murder on Oct. 8, 2014, one year after Arnett's death.

Sinclair filed a motion for a mistrial also, stating that the third video shown by prosecutors was prejudicial to Tresler, because it displayed several minutes of the victim's motionless body.

Goodwin replied that the video was relevant to the case, because it showed the jury what happened that night. He said the Court did a good job balancing evidence, opting to exclude autopsy photographs in the case that might have shown the fatal injuries Arnett sustained when she was shot in the face at a Hannibal convenience store.

Sinclair said the jury instructions did not include some details related to reaching a verdict for each charge and how jail sentences could be scheduled following a conviction. Goodwin disagreed, saying he felt the instructions were clearly written with all the required facts.

Mobley denied the motions for acquittal and retrial, moving on to the sentencing phase of the trial.

Arnett's daughter, Wendy Arnett, took the stand. She said her mother's birthday was two weeks ago, marking the third birthday relatives celebrated without her. Arnett requested that Tresler serve 10 years for each charge consecutively.

“This is a really bad situation for everyone involved,” Arnett said. “Nothing will happen to bring my mother back.”

Sinclair called Tresler to testify. She talked about her sons and the milestones she missed during 20 months of incarceration. She said she gave her life to God in jail, and she said she learned a great deal about the decisions she made with her co-defendants.

“I will never be with anyone like that again,” Tresler said.

Goodwin said video footage showed that the defendants didn't call for help or take Arnett to the hospital.

“Frankly, that's a crime that shocks the sense of justice,” he said.

Mobley said Tresler's actions weighed on his decision to run the sentences consecutively. He pointed out that Tresler did not immediately leave the group to seek help for the victim or immediately cooperate with law enforcement officials.

A Ralls County jury took about two hours to find Tresler guilty of the crimes in March. She is the fourth defendant sentenced in the case — Gary Wiltermood III, Amanda Lehenbauer and Michael Studer — who was identified as the man who shot Arnett — previously pleaded guilty to murder.

A fifth defendant, Cuda Dodd, will appear for trial in August.

Tresler was released to the custody of the Marion County Sheriff's Department for transfer to the Missouri Department of Corrections. Tresler's attorneys plan to appeal the decisions.

Reach reporter Trevor McDonald at trevor.mcdonald@courierpost.com