Let's see if the DNA tests prove it's Maddy's blood. Holiday apartments in busy resorts are covered in all sorts of human DNA and not just blood - ew gross - so it could easily belong to someone else entirely.
But if it IS Maddy's blood then those parents have a lot of questions to answer because I am absolutely sure they know more about this than they are letting on. It wouldn't be the first time a 'distraught' parent turned out to be their child's killer. Either way, Maddy died the night she was 'abducted'; of that I am absolutely positive.