It seems in the rare cases when someone else is left untouched sleeping in the same home during a murder it’s ALWAYS a fucking mystery. I am 100% sure they will find the murderer if there is even a remote connection. If not, then it was a completely random act of targeted violence. Maybe the two girls pissed off some psycho incel, ex con or a serial killer at the bar. He waited outside. Followed them home in his car, and then bam. The couple probably were just unlucky.