In deaths due to scuba diving, All of the following investigations done before, during and after autopsy is of more value except

Investigations in SCUBA diving fatalities : Radiological examination: X-ray of chest in standing position will indicate a fluid level in chest cavity or presence of pneumothorax or pneumomediastinum. Radiographs of knees will show nitrogen bubbles in the joint, indicating a long diving period. In case of air embolism, air samples should be removed with a syringe lubricated by oil for gaschromatography and electron mass spectrometer analysis of gas components. >95% nitrogen indicates nitrogen narcosis. Diatoms test is a test used for detecting antemoem drowning, Not scuba diving.