You can see why. None of it makes a great deal of sense. He's with his wife and a friend at the beach and decides to take off for a hike along difficult terrain, wearing unsuitable clothing, at the hottest part of the day and in 40 degrees heat. He's also 67 years of age. Now a normal Joe Bloggs doing this would be viewed as odd, but a famous doctor who would know all the risks of doing so to do it is even odder.
Also his body had laid there for a good four days in blistering heat before being discovered and apparently a family just yards away had had a picnic. Surely the smell must have been horrendous and aroused suspicion, especially as a full scale search was going on in the area for a missing person at the time?
I'm also surprised given the smell that his body would have emitted and what looks like a barren area to search, that with drones and sniffer dogs it took so long to locate him.