Okay, I have never thought too seriously about RL as a suspect (at least not working alone) because we have all been working with the idea that these might have been particularly violent and graphic crimes (as LE said, they'd never forget it...like nightmares etc.)
But your comment actually made me think of a scenario.
My grandfather, in his elderly years, became more paranoid about his safety. He once came out with a gun, fearing he might need to defend himself, then discovered the visitor approaching him was only a family member. (Yes. Scary.)
What if RL or some other neighbors had been burglarized before and reported trespassers in his barn, what if he or another neighbor were becoming a bit paranoid about their vulnerability as elderly people as well? What if (hypothetical scenario) he or another neighbor had been drinking a little, got scared, and mistakenly shot a girl thinking it was a more threatening person?
Not saying this is what happened, just saying, if police viewed that on the tape it would still be the stuff of nightmares in my opinion. Seeing or hearing two girls gunned down would be something I'd never forget.