Brian Jack was tried three times in Christine’s killing. In 1997, three appeals later, Jack walked away a free man, despite being convicted of manslaughter, after the Supreme Court of Canada ruled it would be an abuse of process to try him again.
http://winnipegsun.com/2013/12/15/she-was-everything-to-me-says-sister-of-christine-jack-25-years-later/wcm/8900f403-1a56-418b-8a96-199824f3b4a8
Tough to achieve a guilty verdict without a body. It can be done, but you need some kind of evidence. That's how they were able to charge that guy who murdered those old people in Alberta a few years ago, even though they never found the bodies.