basically....there needs to be a body.
There is blood evidence that was evaluated by Dr. Henry Lee, and that helped get the guilty verdict.
The property the body is located is very large and has been searched extensively without success.
But she is still there somewhere.
Diabolical killers are getting too many pointers from all the Crime & forensic/investigation shows.
i.e. Stebic, Natalee Holloway.
It appears that the best way to dispose of a body is dumping it at sea/lake or leaving it in deep wooded areas where wild animals will dispose of remains.
There have also been several *medical* related murders - where the perps had access to exotic lethal drugs.
Evil walks among us unfortunately.