When someone kills and then uses an insanity defence.
Mayuko: Did you hear about the Tampa mom who shot her teenage kids for being mouthy?
Phil: What the?
Mayuko: Yeah she said that she snapped but it turns out she had it all planned.
Phil: Good luck using the premedicated murder defence.
Noriko: That Greyhound bus beheading guy was totally crazy don't you think?
Paul: Yeah, premedicated murder for sure.