Insanity a tough defense to mount

Defense attorneys and law professors agree that the insanity defense is difficult and jurors are skeptical.

It comes down to a "battle of the experts." The defense's medical expert testifies that the accused has a mental disease, the state counters with an expert who finds the person sane and the jury has to decide which diagnosis is credible.

"Jurors don't like the insanity defense," said Robert Rigg, associate professor and director of the Criminal Defense Program at Drake University Law School in Des Moines.

This is what Mark Becker, 24, accused of shooting Aplington-Parkersburg football coach Ed Thomas to death, faces in his first-degree murder trial set for September.

He filed this week his intent to claim insanity and/or diminished responsibility as a defense. Becker's is the latest in a recent string of insanity defenses.

Michelle Kehoe of Coralville, charged with first-degree murder and other charges, last month filed her intent to pursue an insanity defense as well. She is accused of killing her 2-year-old son and attempting to kill her other son last year and awaits trial this fall.

Kyle Marin of Cedar Rapids, convicted of first-degree murder for the stabbing and beating death of two women in 2006, was the most recent defendant in this area to mount an insanity defense.

The jury didn't believe he was insane, and he's serving a life sentence in prison.

In fact, only a few cases in the state have succeeded with an insanity or diminished-capacity defense, said Rigg, who has worked on a dozen or so over the past 31 years.

At the Iowa Medical and Classification Center in Oakdale, there are currently only two people found not guilty by insanity, said Lettie Prell, director of research for the Department of Corrections.

University of Iowa law professor David Baldus said this defense is so difficult because the burden of proof shifts to the defendant. In a criminal case, the burden of proof is usually on the state.

The defendant must prove by a preponderance of the evidence that he was insane at the time of the crime, rather than the standard of guilt beyond a reasonable doubt, Baldus said.

"Preponderance of evidence" is evidence with greater weight or more convincing than opposing evidence, said Brian Farrell, a Cedar Rapids attorney and a director of the Iowa Innocence Project. This is the standard of proof used in civil cases.

However, "beyond a reasonable doubt" isn't eliminated. A jury must first determine if the state has proved the crime charged beyond a reasonable doubt before taking up the sanity issue, Farrell said.

This defense also takes a great deal of time because of the medical testing, Rigg said.

"Remember mine were in Polk County, which has a busy docket, but they usually took nine months to a year to get to the trial," he said.

Baldus, the professor, said it's difficult to even speculate on Becker's case because there has been little information made public regarding Becker's alleged mental condition.

Not every kind or degree of mental disease or disorder will excuse a criminal act, Baldus said. Iowa code is specific -- a person must suffer from a "diseased or deranged condition of the mind" that renders the person either incapable of knowing or understanding the nature and quality of his act or incapable of distinguishing right and wrong.