Michelle Kehoe, accused of first-degree murder in the death of her 2-year-old son, will go to trial with a combination of insanity or diminished responsibility defense.

UI law Professor David Baldus said cases that use the insanity plea generally have the threat of serious jail time.

“It is a perfectly legitimate defense to raise,” he said. “Especially if they think the person was mentally ill, and acting in persuasion of delusions. The law acts to only punish people who are blameworthy.”

But getting off on the insanity plea has its drawbacks, he said. Defendants who are found not guilty by the insanity plea must stay at a mental-health facility for treatment and evaluation. The defendants risk spending more time in the facility than they would have in prison, if they had been found guilty.

First, insanity and diminished responsibility pleas must pass the judge or jury.

“I certainly think that it is a tough sell to a jury,” said Matt Lindholm, a defense attorney based in Des Moines.

He said judges and juries look for evidence of mental issues, which requires an evaluation by a psychologist or psychiatrist prior to the trial.

“She has raised it, so we will have to deal with that,” said prosecutor Allan Vander Hart, the Buchanan County prosecutor.

Despite the insanity plea’s reputation in the public mindset, it is a legitimate defense strategy because of the nature of mental illness.

“Often, people are walking around mentally ill, and they are not aware of it; frequently, some event triggers the onset of mental illness,” he said.

Eugene Kehoe, Michelle Kehoe’s husband, reported that his wife and children were missing in October, 2008.

Michelle Kehoe went to a Littleton, Iowa, residence the following day, informing the owners that her children were in danger.

Buchanan County authorities discovered Seth Kehoe’s body near the Hook ’N’ Liner Pond, close to Michelle Kehoe’s minivan. They discovered Sean Kehoe alive but severely injured.

He told police he was wrapped with duct tape around his nose, eyes, and mouth by his mother before she cut his neck.

She was arrested and charged Nov. 5 with first-degree murder, attempted murder, and child endangerment causing serious injury. Kehoe is set for trial Oct. 28.