What led to the first successful plea of mental disease in Mid-Missouri?

POSTED: 05:57 PM CDT Sep 24, 2013 
COLUMBIA, Mo. -

A day after a man accused in a Mid-Missouri murder lands in a mental hospital, we're taking a closer look at the decision that landed him there and kept him out of prison.

Monday, 34-year-old Rudy Perez, charged with first-degree murder after killing 78-year-old Robert Hill in the V.A. Hospital in February, was essentially acquitted after prosecutors accepted his plea of not guilty due to mental disease or defect.

Barry Langford, a former prosecutor and current professor at Columbia College, said he would have made the same decision if he was the prosecutor.

"There was a history of mental illness, the crime occurred where he was being treated for mental illness, so it was a very strong case," Langford said. 

This is the first time Langford can remember that a plea of insanity was successful in Mid-Missouri.

He said that a plea of mental disease is actually only used in about 1 percent of felony cases, and it is only successful about 25 percent of those times.

Langford does not believe this successful plea will cause a trend in the use of the insanity plea because it is so hard to prove.