Taking a moment to collect my thoughts.
NG is missing. That alone makes this an outlier. A break-in or SA, if there was a murder at all, no need to remove the victim. Unless for fear of DNA. But I don't think the details align with that all.
So why is she missing? Due to age/blood thinners, IMO it's entirely possible that her injury was unplanned, may have resulted from her mobility challenges, in which case, she would have gone missing with no sign of injury.
Why?
To hide DNA in the case of SA. If there was SA, I think LE knows that, based on the appearance of the crime scene.
If no obvious signs of SA, again, why is she missing?
Perpetrator needed her alive.
To aid in relocating her? Too heavy to carry? Force her to walk...
In order to swindle her? Take her to an ATM/Bitcoin and hope she has assets she can convert for you?
It's an anomaly. 84 year old victim. Missing. But likely alive when taken from her home.
It's easy to say that ransomers might be capitalizing on a news story. We know of one already.
But what I can't get past is that, if not as a set up for ransom, why was she removed from her home?
JMO