Has the New Bedford Highway Killer been mentioned in association with this case? He was active right at this time, and one of his victims was from Fall River (Debra Madeiros). The remains of two of his known victims have yet to be recovered. He's associated with murders of sex workers, I sincerely doubt he exclusively murdered sex workers. Especially in light of the fact that he obviously went to great lengths to conceal remains in two known cases, I'm assuming there are more victims.
It definitely doesn't sound like it was the case that this woman just took off with some other man. I wonder why this was offered as an explanation.