Nowdays LE can actually pinpoint with more or less accuracy where everyone was assuming they had their cellphones turned on and with them. So if boyfriend went out that night at some long distance from his house with his cell phone (or didn't) LE should know. Of course LS lost her cell phone that night, so they can't pin point her location.
But, if this were the case, why would they not be putting more heat on him? If he were out when he says he were home it would an obvious lie and would put most, if not all of their focus on his whereabouts and actions that night. If JW left his home that night I would assume it would make him suspect #1 and that he would have been brought in for several rounds of questioning, at the very least.