HUDSON, Wis. -

Jurors in western Wisconsin say a father had a mental defect but is still responsible for killing his three young daughters last July.

Aaron Schaffhausen pleaded guilty last month to three counts of first-degree intentional homicide in the deaths of 11-year-old Amara, 8-year-old Sophie and 5-year-old Cecilia. But he argued he was not responsible because of a mental illness.

Jurors deliberated for about 3 1/2 hours before reaching their verdict.

During closing arguments Tuesday, prosecutor Gary Freyberg said Schaffhausen was in control of his actions and was a mean, callous person -- but not legally insane.

Defense attorney John Kucinski argued Schaffhausen has a rare mental disorder, rooted in a deep dependency on his ex-wife.

The jury found he had the capacity to know what he did was wrong.

Attorney John Kucinski says Judge Howard Cameron instructed the jury on motive when it wasn't relevant to the case. He also said the judge shouldn't have denied the jury's request to have expert reports in the room as they deliberated.