For centuries, whalers, pirates, and ship captains who sailed in that area used the island for fresh water, coconuts and ship maintenance. It was a nice, sizable, uninhabited island lying over 300 miles off the Central American mainland, where the loot could be hidden without any interference. Cocos Island's landscape has not changed much over the years.
It is a dense, hilly jungle covered island, with more than 200 waterfalls and over 300 inches of rain a year. It has an irregular coastline with two bays on its north side. The Mary Dear pulled into one of the bays and dropped anchor. It took eleven boatloads to remove all of the treasure onto the island.
After much consideration, a spot was chosen to bury the loot. The plan was for the crew to meet again after the revolution had calmed down and unearth the treasure and bring it home to England. That would not happen...
Shortly after leaving the island, the Mary Dear was captured by a Spanish "man-of-war". The commander of the Spanish ship knew of the deal between the Viceroy and Captain Thompson and wanted to know what happened to the treasure. When no one told of the treasures whereabouts, The Mary Dear and her crew were taken prisoner and conducted to Panama. There, they were all put on trial for murder and piracy. Everyone was sentenced to hang. By the time the last crew member was hung, Captain Thompson and his mate, James Alexander Forbes I, made a deal. If their lives would be spared, they would lead the Spaniards to the treasure.
The two prisoners were taken to Cocos Island and while pretending to take measurements, the men slipped away into the dense jungle. The Spaniards searched for the men, but it was impossible to find them. The disappointed crew finally set sail back to Panama.
Thompson and Forbes remained on the island living off of coconuts, bird eggs, fish and small game. Sometime in 1822, a British whaler, who had stopped at the island for fresh water, picked them up. When asked, the men said they had been shipwrecked. This made sense and no further questions were asked. The whaler set anchor at Puntarenas, on the Costa Rican coast.