Body fluids are not at all like mud puddles, they are more viscous and oily.
if real sandy it would just sink way down maby 8-10 feet i think it was right there otherwise parts would of came off like hair and skin maby even limbs
8-10 feet??? okay.......
As far as the last part of you post, I can not make any sense of it. Parts of the childs body were missing, and as far as I have read the transcripts - no one ever did any forensic soil testing to prove/disprove whether or not the body had lain there since death.
Although I am a bit confused as to what you think was "right there"