Sadly, until her body is found, if it is ever found, I don't think we'll ever know what truly happened to Bobby. For all we know, he could have done his own cremation of her- I know that sounds God awful, but seeing that so far, there isn't any evidence of her whatsoever taking that trip with him, he could have done just about anything with her. Tossing her in the river sounds like a pretty handy excuse- it can take a long time before a corpse shows up in the river, and even then, it can be pieces of clothing, bones, etc that show up a year or so later. This is just so sad for her family- my heart breaks for them all.