HUDSON (WITI) -- Aaron Schaffhausen is accused of killing his three daughters -- and is currently on trial in Hudson. He admits he killed his children, but says he is not responsible because of mental illness.
"He was a sad little boy,' Schaffhausen's mother, Susan Allen said.
Allen describes her son as a little boy with big problems -- who didn't connect with adults and had very few friends.
"He was our challenge," Allen said.
Allen claims her son has had mental issues since he was young. She talked about her mental illness, and that a relative on her side of the family also dealt with mental illness.
Schaffhausen's father Roger said their relationship got better when Schaffhausen became an adult and a father. He showed never-before-seen pictures of his son and grandchildren together and said his son loved his children, but fought depression.
Dr. Ralph Baker is a court-appointed medial expert. He provided jurors with disturbing details of Amara, Sophie and Cecilia's last minutes alive.
"The next thing he knew, he had her neck in his hands and he was strangling her," Dr. Baker said.
Dr. Baker says when Schaffhausen realized Cecilia wasn't dead, the other girls came inside the home. That's when Schaffhausen admitted to killing them.
Dr. Baker testified that Schaffhausen knew right from wrong when he took the lives of his daughters.
If Schaffhausen is found guilty but insane, he will probably be sent to a mental health facility instead of a prison.
The trial is expected to last several weeks.