Story highlights Aaron Schaffhausen killed his three daughters, ages 5 to 11, last year

Judge: The three life sentences must be stacked, not served concurrently

Schaffhausen's attorney says his client suffers from mental illness

A 35-year-old father found to be sane when he killed his three young daughters last July was sentenced to three life sentences without the possibility of parole Monday.

St. Croix County Judge Howard Cameron said the lives of sisters Amara,11, Sophie, 8, and Cecilia, 5, were each so important that Aaron Schaffhausen had to serve each sentence consecutively.

"Each child has to be recognized as an individual girl," Cameron said. "To make it concurrent would diminish what happened to those young girls."

Schaffhausen and his wife Jessica had recently divorced when he came to spend the day with his daughters last year.

According to the criminal complaint, Jessica -- who was not home at the time -- told police that two hours after Schaffhausen went to see the girls, he called her and said, "You can come home now because I killed the kids."

Jessica, who was in court Monday, was quiet throughout the proceedings. But her sister, Mary Elizabeth Stotz, called Schaffhausen an "evil coward" who "should rot in hell" during the victim impact statements.

"Aaron Schaffhausen, the man who helped genetically make those girls and shape them ... Aaron became the darkness, the boogeyman, and the monster under the bed," Stotz said. "He was so evil that he took their unconditional love for him and used their love to lure them close enough so he could kill them. Their last memory is what an evil killer their dad was."

Stotz also expressed fear that if Schaffhausen was allowed to be released on parole, he would get revenge on her family.

Schaffhausen sat through the proceedings with no visible emotion, avoiding eye contact and almost inaudibly saying "no" when the judge asked him if he had anything to say.

His attorney, John Kucinski, emphasized that his client suffered from a "rare mental illness" who committed a "rare catathymic homicide."

"Nobody wins in this case," Kucinski said. "Both families suffer, Jessica suffers, uncles, aunts.

"You can say, 'Three young girls are dead, we've lost their lives, he did it because he hated Jessica, let's get our revenge.' Or you can try to actually take a look at mental illness and prevent things in the future," Kucinski said.

A large photograph of the sisters stood by the judge, who finished his sentencing by saying, "People in general, there is sometimes an evil, and there is goodness," Cameron said.

The girls' aunt remembered them as "amazing people."