A man convicted of murder in a 2017 cold case has filed a motion for a new trial.Wilbert Smith was found guilty of first-degree murder earlier this month in the killing of Xavier Bass.Bass was shot on Highway 75 near Hamilton Street in 2017.'Start the process of closure': Shooting victim's family relieved after suspect named in 2017 Omaha murder. See the story here.According to court documents, Smith alleges there was "irregularity in the proceedings" preventing a fair trial.The motion was also filed due to the verdict "not sustained by sufficient evidence or is contrary to law," according to court documents.Smith is scheduled to be sentenced on Feb. 21.Click here for the latest headlines from KETV NewsWatch 7