Extensive Research
His extensive research had led him to the conclusion that the Japanese forces had a medical facility located somewhere in that section of the jungle. Based on his readings of the battle maps and old diaries, his suspicions of a Japanese medical facility nearby were indeed true. Sadly, Freeman and his team were not able to locate the exact area of the Japanese medical facility until that moment.
Confirmation
His theory was confirmed when they came across some very interesting pieces of evidence. Because of this, he was able to officially conclude that there had been a Japanese hospital there back in September 1942.