Part One: Old Treasure
The diary was written by a clergyman - at least that is what the quality of the Latin and the general religious fervor of the entries suggest.
Then entries written after Columbus´ departure to Europe are at first mostly concerned with longing thoughts about bringing the one true faith to the heathen natives, as well as grumblings about the blind greed of their fellow Spaniards in La Navidad. Apparently a number of the people left there went on excursions to search for gold and other valuables among the nearby native settlements - and found a considerable amount of it. Unfortunately, they also aroused the anger of the aforementioned natives, leading to several ambushes against gold-seeking excursions and later on foragers, and ending with a siege of La Navidad and finally the outpost´s destruction and the massacre of its inhabitants.
The final entry reads: "Drums... drums in the hills. We cannot get out. They are coming!"
An earlier entry gives directions to where one of the gold-seekers claimed their finds were hidden, though it leaves unsaid how the author got that information - confessions of a repentant sinner, perhaps? The directions are clear enough that, if the local geography has not changed too much in the last century and a bit, it should be easy enough to find the place.
There is one sentence, though, that seems worrisome. The author remarks on the folly of a sailor named Ramirez who "took the treasures that the natives regard as sacred, and is now doomed to guard those same treasures". The author claims that the other sailors demanded his help in dealing with Ramirez´ affliction, but he refused, reminding them of the wages of the sin of greed.