What about Levi Aron?
Levi Aron spent close to 36 hours of time with the boy under his control. He has MI but was NOT in a manic state for 36 hours when he was carefully calculating how to not get caught crossing state lines to attend a wedding with a young boy. His final act may have been manic. But, the entire episode show premeditation and calculation.
This is why he simply pleaded guilty instead of wasting time with an insanity plea. His actions leading to the final manic episode show he knew he was doing wrong, etc.
So NO, Levi Aron is a pure rasha.