We are not reluctant to consider that he did it, in fact history suggests that he likely did do it, that is how most of these cases work out. That said, the actual evidence proving that is (as far as we know) sparse to non-existant. We can't even be sure that she actually has been abducted, we just know she is missing. Whatever he did or didnt do prior to VS's dissappearance, whatever she did, is not evidence for what happened that monday, neither is what someone else did in another case. That sort of stuff is inflammatory which leads people to make conclusions on emotion, not solid facts.
If they really want to make a breakthrough in this case, then finding VS, dead or alive, is the top priority. Once that happens, or if it happens, things will likely moe pretty quickly.
There may well be solid facts we don't know about, but known to LE, in this case, but until we know those facts the jury is still out.