Sarah Knysz took the stand Monday in the trial of her husband, Eric Knysz.

He faces charges for the shooting death of state trooper Paul Butterfield in September.

WOOD TV reports Sarah Knysz was emotional as she told jurors that her husband shot Trooper Butterfield during a traffic stop because he didn't want to go to prison for driving on a suspended license and having stolen guns in his vehicle.

The suspect asked his attorney not to cross-examine Sarah Knysz after the prosecution finished.  She faced her own charges in the case, for having helped the suspect flee the scene of the shooting.  As part of a plea deal, she's testifying against him.

Sarah Knysz was pregnant at the time of the incident.  She gave birth to a son on December 25.  Eric Knysz apologized for causing stress to them and the rest of his family.

Jurors on Monday also heard another recording of investigators' interviews with the suspect.  Knysz is heard on tape talking about the shooting, and saying, among other things, that he wished he could change it so he was shot by the Trooper instead.