An autopsy found on Saturday that the child whose body was found inside a bag weighted down with an anchor in the ocean off the Spanish island of Tenerife died from drowning.
This comes as rescuers prepared to resume the maritime search for her infant sister.
Tomas G., the father of the two little girls Olivia and Anna is the main suspect in their disappearance after he failed to return them to their mother as agreed at the end of April. He is also missing.
According a statement from the Canary Islands Superior Court, an autopsy found that Olivia, 6, died from pulmonary edema, or an excess of water in the lungs.
Rescuers prepared to resume the hunt for Anna, 1, and her father after returning to port in Tenerife due to technical problems with the search vessel.