HUDSON, Wis. -- An expert hired by prosecutors to examine Aaron Schaffhausen testified Monday that he believes Schaffhausen was sane when he killed his three daughters in July.

Dr. Erik Knudson testified that his medical opinion is “very strong” that Schaffhausen understood that what he was doing was wrong and was in control of his actions, which is part of the test for legal sanity in Wisconsin.

Schaffhausen’s deceiving of his ex-wife and others to get access to the girls while he was visiting from North Dakota, as well as him acting appropriately in public in the days and hours leading up to the crimes, then trying to destroy evidence led to Knudson’s opinion, Knudson testified.

Knudson, a psychiatrist, reviewed evidence and interviewed Schaffhausen for more than 6 ½ hours in March, longer than would be typical because Schaffhausen didn’t answer all questions, gave rehearsed answers sometimes and it became “tedious” to get information from him, Knudson testified in front of a St. Croix County jury.

Contrary to the reports of others, Schaffhausen told Knudson that he hadn’t threatened to hurt the girls and that his ex-wife Jessica Schaffhausen misunderstood a conversation and overreacted, Knudson said.

Later, Schaffhausen told Knudson that he didn’t know why it happened and that he was in a “dreamlike state,” Knudson testified.

“He said that he was out of control when this happened,” Knudson said, adding that Schaffhausen told him of two other times he was out of control — both ultimately involving aborting plans to come and kill the girls.

Schaffhausen has pleaded guilty to killing 11-year-old Amara, 8-year-old Sophie and 5-year-old Cecilia in the girls’ River Falls home on July 10. His attorneys are trying to prove by a preponderance of evidence that Schaffhausen was insane at the time and should be sent to a mental institution instead of prison.

A defense mental health expert testified earlier that Schaffhausen was insane; a court-appointed expert found Schaffhausen was not insane.

Knudson diagnosed Schaffhausen with “major depressive disorder” along with alcohol dependence and anti-social personality disorder, he said. But none of those diagnoses meant legal insanity, he testified.

“Depression did not cause Mr. Schaffhausen to do what he did,” Knudson said.

To find that Schaffhausen was insane, Knudson said, he would have needed to see something prominent and observable before and after the crimes.

Knudson’s testimony is expected to continue Monday afternoon, with closing arguments to follow at some point. The jury could get the case Tuesday.