I've never bought the abortion angle. The timing makes no sense. There was a toddler upstairs who could wake up at any time. Yes, he was 2, but by that age my kids had figured out how to escape their cribs. Her 4 year old could have come home, possibly with the neighbor, at any time, especially since Joan never even told the neighbor she was dropping her daughter off in their yard. Sounds far too impromptu and risky for a clandestine medical procedure.
And where was this abortion supposed to have happened? The vast majority of the blood was in the small kitchen, with only a few drops found upstairs. I've never seen any mention of blood in either bathroom.
I question both the highway sightings as well. It's not unusual for people to misinterpret what they've seen or think they've seen or to make up sightings or details to be "helpful". The fact that no others came forward to say they also saw this woman or attempted to assist her makes me wonder if the two sightings on different highways are red herrings. And where would she have gone from there?
I do think the sighting of the old, dirty unknown car in her driveway is important. The blood trail ended in the driveway, and I think that's probably where the clues end as well. Did Joan know someone was coming to see her? Someone she didn't really want her daughter to see? It just seems odd that she'd deposit her four year old across the street without a prior plan or so much as a brief warning that she'd returned the kids to the neighbor's.
Could this have been staged by Joan? I suppose it's possible. We never really know what's going on with someone else. But here again, it seems so impromptu and I don't believe she walked away from the house. There would have been more sightings and someone staging a disappearance would probably have avoided highways. And I find it hard to believe she just "dropped" into a construction site, never to be seen again. So someone would have had to take her away from the scene by car (the old dusty one?) and lead her to her new life.
If she didn't stage the scene, someone took her away, almost certainly against her will or under a threat that her little boy would be harmed if she didn't go along. Lincoln was probably an even quieter, safer place than it is now and it's hard to imagine an unknown assailant just wandering into that obscure neighborhood. And I'm still stuck on the dropping off of her daughter and neighbor boy (across a street the little girl had never crossed alone before this) without telling/checking in with the neighbor. Unless her little boy was being held hostage, she could have asked the neighbor to call the police. And the little girl saw no one, so this must have all happened before any assailant arrived at the house.
So I'm left to conclude that Joan probably knew her assailant and knew he was coming to see her. Boyfriend? Mentally ill/disgruntled family member? Who drank the beer? Why are the blood patterns so odd? Who tried to clean up the kitchen - and why? Where's the weapon? And where's the body?
All my speculation, of course. But this is a wild one.
Agree with all of this. She was taken against her will, but had just enough notice that she could take her daughter next door. I've also questioned her just dropping the kids off at the neighbors without telling the mom. It doesn't sound like the kind of thing most moms would do back then unless it was really important. As you say, the person was probably threatening to harm her son. After that, she was taken away in the older car.
One of the more frustrating items in the investigation is that LE claimed they were finally able to track down the owner of the car seen in her driveway. IIRC, someone in the neighborhood saw the car and managed to recall some of the license plate numbers. The owner of the car lived somewhere across town, but after discovering it, LE chose not to pursue it further. No reason was given.
The Risch marriage seemed to be fine. The blood in the kitchen was probably from Joan being struck by her abductor as she used the phone book to call for help. It seems unlikely it was a secret lover. She seemed to be frightened of them and they used violence against her. I think there's a small possibility it was an attack by a stranger who had been stalking her. The police did investigate people at the nearby military base. I think it was an Air Force Base.