It has nothing to do with DNA. It would have to do with her being exposed to that. (if true)
Don’t know if she’s for real or not.
But even in her claims it appears she didn’t understand what was going on.
He told her various explanations for things like the sound of gunfire (firecrackers) or the presence of a gun in the car when he made sure to hide it from cops, etc.
She’s not claiming to have understood it or actually watched the killings, if I read it right.
But was along in the car during the time frames.
Be that as it may, the insistence that she should be suspected of copying his actions later in her own life is a bridge too far, IMO.