In hindsight tho, the drowning theory was brilliant because it could never be proven one way or the other because there was nothing but bones left of the little girl and you can't prove or disprove drowning without lungs.
Yes you can if the conditions are right.
Those conditions are:
1- Victim drowns in a body of water that is exposed to the elements for some time. AKA a pool, swamp, sea, lake or river. Not a kitchen sink or bathtub.
2- There is bone marrow left in the long bones (femur/humerus).
In this case there was no bone marrow left in the long bones because they had been scavenged by predators. Normally in an adult human the predators cannot get to that marrow but in a child's bones they get to it easily.
The evidence of drowning is left in the bones via diatom absorption. As the victim drowns, the water enters the lungs and comes into contact with the alveoli...which allows the algae-like diatoms to be absorbed directly into the bloodstream. In the half a minute that it takes the person to drown, the hearbeat will carry that blood to the long bones where the marrow absorbs the diatoms and they are left there as evidence.
A normal human has an extremely low, almost insignificant diatom count in their bone marrow..but when the drowning takes place the diatom count significantly increases above normal levels.
Now this is not a 100% definitive evidence of drowning since some people do asphixiate first before drowning (holding breath until they pass out and then the water gets in the lungs...and thats not enough time for the blood to pump the diatoms into the long bones) but when its present its a big red flag to the cause of death being drowning.
