IMO, there are many similarities to the case of Missy Bevers:
Killer is on a mission, seemingly has to fulfill an order.
Killer is in a striking disguise, not disclosing, if he is female or male (for years!!).
The killer appears on the surface in the early morning. Knows, when the victim will show up (and THAT they in any case will show up).
The husbands both have a strong alibi for that time in the morning of murder.
After the murder both of the husbands are the least impressed of all those left behind.
The husbands both are involved in a family business and have financial issues.
The night of the murder, hours before, the killer himself or an accomplice (or both) is cruising parking lots in the vicinity. One wonders, why they show up so very early. One wonders, what they do in their car for pastime until the killing.
The killer (by chance?) prefers the brand NISSAN: Missy= Nissan Altima; Liz= Nissan Frontier.
The killer gets each car managed without showing the license plates in a way, that they are readable.
The murder itself happens similar: an attack at close range.
The killer uses a gun.
The killer has to ensure, that the victim is 100% dead, and he does.
The killings happen at a location, where a short time later several people would appear and perhaps destroy the traces, unwillingly.
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Did I forget important things?
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BTW, in case Missy B. we saw stills of the surveillance video (parking lot). In the Nissan Altima we thought to recognize a blonde woman on the front seat or a big blonde dog (Retriever). We weren't sure. - My thought today is, that the blonde hair mane looked quite similar to Liz' killer's blonde hair mane. Should I include this --->

?? Idk. I'm actually serious.