IMHO I think that anyone would realize that another person's baby would "mean everything" to that person/couple. Unless it had been proven in the past that the baby didn't. I have seen nor read zilch indicating that.
I tend to fall into suspecting someone more like Israel Keyes (deceased) who planned insane murders @places that had nada to do w/him.
I know everyone here is familiar w/Keyes and others like him. Just for example:
https://en.wikipedia.org/wiki/Israel_Keyes
[Keyes planned murders long ahead of time and took extraordinary action to avoid detection. Unlike most serial killers, he did not have a victim profile. He always killed far from home, and never in the same area twice. On his murder trips, he kept his mobile phone turned off and paid for items with cash. He had no connection to any of his victims.]
Much more @link. These killers are travelers and do strike in very remote areas.
jmho
additional interesting about Keyes:
[he flew to Chicago, and there rented a car to drive the 1000 additional miles to Vermont]