Possible Motives for Stranger Abduction
It doesn't have to be a motive or reason that any average, mentally and emotionally healthy person would understand or ever think of. It could have been random with time, place and circumstances in the criminal's life at that moment. Blind rage, just wanting to hurt someone and made an instant decision to do it.
• “Just Because”
• Crime of opportunity: doesn't matter who the victim is, only that the opportunity presented itself. Maybe they've done it before, maybe they've been thinking about it for years (not necessary in any detail, just “I wonder what it would feel like to...”) and this situation became available.
• An accident (unintentional or recklessness) that led to the driver wanting to prevent the victim from talking. There was no intent in harming anyone, they did it as a by-product of thought to protect themselves.
• An accident-on-purpose: bump the bike enough to dislodge the rider, maybe incapacitate them. Offer to help or give them a ride to the hospital, etc. Once the victim's in the car and trapped, off they go.
> for sexual purpose
> for non-sexual, torture purpose
> for thrill of straight out killing someone
> for money: force victim to withdraw cash, or give their PIN
> for money: ransom with no intention of letting the victim go
• A stranger, but had seen her before and became fixated on her. Stalking her for an opportunity. Video from days before the assumed
Or a non-stranger who has known her, superficially or not, for a long time and takes a chance that goes horribly wrong and …
Possibly he knew she would be alone that day. Possibly, he knew her well enough to drop by to check on her and made an unwanted advance and there was a struggle or worse. Knowing that she could have told her husband or others that so-and-so might drop by, he made it look like she went on a bike ride. He planted something on the road 'just in case' to direct or misdirect a search. It's possible he didn't want the bike actually found.
She may have gone for a car ride unwillingly with him and been able to toss or drop something out the car window as a clue. Maybe the single item was run over by traffic and broken into multiple pieces. Those multiple pieces could be stated as item(s) plural or as a single item when put back together.
She may have gone for a ride and then realized she was being followed or someone stopped and it didn't look good for her, so she left/dropped/tossed something that she hoped would be found as hers.
If she left for her ride at 4:30p, it's reasonable to assume that she'd ride a trail close to home and there's no need for her to go up on the highway when there's a direct trail from their home to the Colorado Trail and Fooses Lake/Dam.
Randomness depending on what was found on the up on the highway, it could have been something of hers completely unrelated to her disappearance. Dropped at another time, flew out the car window, etc.