Amy Marie Derewitz disappeared after a confrontation with her ex-boyfriend, David Kniga. He pleaded guilty to manslaughter in her case and stated that he put her body in a dumpster. Her body has never been found.

Charley Project link:
http://www.charleyproject.org/cases/d/derewitz_amy.html

I am hoping that someone can comment on landfill searches and how often they're successful. I know that some bodies have been recovered from landfills.