Lyon County District Judge David Peterson ruled this week the attorney for Olga Marina Franco Del Cid can make the argument in court.
Also, lawyer Manuel Guerrero may argue the boyfriend's alleged flight is evidence of his guilt. The boyfriend, Francisco S. Mendoza, has not been found.
Prosecutors claim Franco was driving the van that crashed into a school bus in February near Cottonwood, killing four Lakeview School students.
Franco's trial is scheduled to start in Kandiyohi County District Court in Willmar on July 28. Peterson previously granted a change of venue from Marshall.

