Another what if...
This is a long shot & maybe I've read too many True Crime stories,
but here goes my latest theory:
What if MS did not like RN and felt she caused his parents' divorce &
broke up his family. Did DS tell MS how horrible she was? Was MS a
"little monster" to RN? Did she have trouble getting along with him?
If so, this may have been what caused trouble between RN & JS
(if there actually was trouble). Maybe JS decided, since they couldn't
all get along, and/or his son said how much he disliked RN, or made up
stories about her..... JS decided he had to break it off with RN.
The break-up devasted RN to the point she decided to kill herself &
make it as dramatic as possible.... or to make it look like it was a murder.
But before she killed herself, she decided to take MS out with her...
as a way to get back at JS.
My only problem with this theory is:
Why would she wait so long between the 2 killings? Did she have them both
planned for the same day, but something happened that she couldn't take her
own life the same day. Like maybe the kenneling the dog issue?