Well machtuk, as you can clearly see from the prop in the photo the damage indicates that it wasn't spinning at the time so I'd likely say fuel exhaustion, there is also a lack of explosion or fire after the crash which is a pretty clear indication. I'm also fairly certain the Pilot was wearing a white t-shirt which may have caused glare preventing them from seeing the fuel gauge which is obviously the cause of all this. Their shirt also likely stopped them seeing how much fuel they uplifted at the beginning too. If someone can please retrieve the METAR from their point of departure at the time of departure we'll likely see it was CAVOK which meant full sun and therefore full glare, we'll also likely see tropical temperatures which would have precluded the use of a standard navy blue cardigan that would have otherwise prevented this glare, if they'd waited for a colder day this would never have occurred.
Just to be clear I'm not actually having a go at anyone or being in anyway serious I just figured I'd try giving my "professional air crash investigator" opinion for a change