Chad Isaak will be sentenced for his quadruple murder convictions on Dec. 28.

Morton County Court documents say the hearing will happen at 8:30 a.m. in a Mandan Courthouse. Judge David Reich ordered a pre-sentence investigation and an opportunity for victim impact statements.

Isaak was found guilty in August after a three-week trial on charges he murdered four RJR Maintenance and Management employees in Mandan on April 1, 2019.

The jury deliberated for four and a half hours over two days, when they convicted the Washburn resident and chiropractor.

Isaak was also found guilty of burglary for unlawfully entering the RJR building while it was closed to the public, unlawful entry into William Cobb’s RJR vehicle and unauthorized use of the RJR vehicle, which was driven to Indigo Signs shortly after the killings at RJR.