Do they know they lie?

So as we know narcissists and serial killers often chronic liars. Many serial killers never admit they killed someone. Not even when all evidence is clearly against them, they will still be victims expecting people feel sorry for them. They blame it on system, on their mother, on their mental illness, which i sometimes believe is. But then i ask myself if they are really victims of mental illness, why they didnt seek help.

My narc was chronic full time liar as well. He very often said ‘ i never said that’, even if i showed his message up his nose, he would never admit it. If you look at the serial killers Pierce Morgan interviews in jail, he interviews those killers who refuse to take responsibility for their actions, say they re innocent. They are acting so well they could get Oscar nomination. I recommend to watch its on Youtube) and i am wondering, do they deep down see themselves as a serial killers/ abusers or they completely lack self awareness and live constantly in delusion?

Experienced psychiatrists think that narcissists are always aware of reality, always know they do right or wrong, so it might be different with psychopaths living in psychosis, who knows.

Did your narc ever shown self awareness? Do they know they lie? I think the very intelligent ones have higher self awareness perhaps?