Leave Bazaar and take dish of dog food from open cell -- do NOT feed this to dog until you can put drug in it. Go to (now) empty tent of man and take shoe. Notice rifle. Leave and go back to cave. Use metal file on 'strange door' to get filings of the lev. metal. Exit to map and go to Carib Island.
Talk to painter two times. Give her photo of Easter Island. Give her 'M' parchment to use as canvas. Go to pier and tell sailor that you've found Tobias. Exit and go back to Desert Cave
Go to Village beyond the cave. Enter butcher's shop. There should now be a piece of meat on dish on counter. Talk to butcher. You should find out that this is a camel carcass. Use jar of termites on the hunk of meat. After shopkeeper faints, take narcotic powder and the rat bait. Go to Fort and use narcotic on dish of dog food. use on dog. Take small safe. Enter door and notice large safe. Use chest -- it moves to reveal a passage. Enter. Take the silencer from floor. Use wall-steps to go to roof. Take cartridge case. Take telescope lens. Use shoe from tent with footprints in the corner. Return to fort area and talk to guard. You should be starting to tell him about evidence. But he still needs more proof. Exit to map.
Return to the archeological dig below church and find rat -- either below stairs or all the way at the iron bars at right end of dirt floor. Use rat bait on rat. Take the sleeping rat. (you won't need him for quite a while!). Return to map and go to Easter Island.
Go to Tobias' hut and give small safe to him 'to crack' He will tell you combo is 517. 'Use' safe and it should open. Get key inside. Return to Desert Fort.