The guy's name was Rex Krebs, if you want to google and read about him. I think Holly's abductor would probably be similar to this guy, actually.
He was a sex offender who spent time in prison for rape, but was eventually unleashed back onto the public and the two women he eventually murdered. He knocked the first one in the head in a public place, tying her up, transporting her in his truck to a cabin, where he raped and murdered her.
The second victim was someone he stalked for a while. Krebs had a rape kit that included binoculars and rope. After multiple occurances of peeping tom type stalking, he eventually broke into her home, beat her unconscious, and transported her in his truck hogtied.
Even though they showd a knife on the TV show, it sounds the blood at the scenes were from hitting the girls with blunt objects and perhaps his fists.
I do think Holly Bobo was probably abducted for sexual motives, just for the simple fact that she's a pretty girl. It sounds like Parsons is a very, very small town, so I imagine the number of females who are young, pretty, and height/weight proportionate would be very low, making her a rare beauty for the town and elevating her risks for something like this, unfortunately.
A perpetrator who would do something like this is obviously somebody totally out of control, very dangerous, and someone who is likely to do this again, in my opinion.