I'm thinking drug-related as well. The whole thing is so irrational and "out-there," I cannot imagine anyone in their right mind doing something like this. Who would think that they wouldn't be caught after ransom exchange in this day and age ("Local and federal law enforcement agencies contacted a kidnapper and
negotiated for several hours, ultimately agreeing to pay the ransom." BBM)?
One possible scenario: The perp(s) think Sandra and her husband have a fair amount of cash and/or valuable items stashed away at home due to the husband's jewelry/pawn business and break into the house thinking that no one is there; Sandra happens upon the scene of the crime, the perp(s) flee the scene, taking Sandra with them, but they kill her as soon as Sandra gives up her cell phone and the number for her husband's number at work, in order to eliminate the witness:
"Kennewick Police Sgt. Ken Lattin said 69-year-old Sandra Harris was
taken Friday by someone she knew. Lattin said her abductor then used Harris' cellphone to call her husband at work to demand an undisclosed amount of money in exchange for her return.
'This was not a random act,' Lattin said. '
They're not related. We're not exactly sure what the nature of the relationship was, but this was not random.'" (BBM)
Angry that they weren't able to take anything from the home, they then demand a ransom. Poor Sandra ... she must have been so scared

.
Above quotes from:
http://www.oregonlive.com/pacific-n...f/2016/11/fbi_searching_for_abducted_was.html
Official FB of ACE Jewelry and Loan, owned by Sandra's husband, Randy:
https://www.facebook.com/Acejewelryloan/
ACE Jewelry and Loan business website:
http://www.acepawn.biz/