I remember watching a tv show or movie like law and order or psych and the murderer
Tried to explain himself but they didn't let him or something and they explained how murderersloveexplaining just before they kill? Anyone know the term or phrase?
bump
lulz?
As ahenkel said, it's allocution. Said many times on Law & Order episodes as you might expect. Basically the DA demands the defendant completely explain his actions truthfully as part of a plea agreement.
I think the op's talking about something else here. As you said, allocution is when the prosecutors and/or judge require full disclosure from a defendant before a plea deal, but the OP seems to be asking about the plot device where a killer/supervillain can't help but explain himself to his upcoming victim.
I don't know if there's really a word for that beyond "plot device."