SLIDESHOW: Witnesses in Schaffhausen Trial

Updated: 04/05/2013 1:42 PM By: Maricella Miranda

Testimony continued Friday in a trial for a man who admitted to killing his three daughters last July at his ex-wife's home in River Falls, Wis.

Coworkers Jon Paul and Jeremy Michaels testified that they were playing cards with Aaron Schaffhausen when Schaffhausen said he wanted to kill his ex-wife, the man she was dating and Schaffhausen's children, 11-year-old Amara, 8-year-old Sophie, and 5-year-old Cecilia.

Schaffhausen, 35, has pleaded guilty to three counts of first-degree intentional homicide, but he maintains he is not responsible for his daughters' killings because of mental illness.

The jury trial in St. Croix County District Court is to determine Schaffhausen's sanity at the time of the killings.