The enemy withdrew to the ruined fort at St. Simons, where they were sheltered by the guns of their fleet. Oglethorpe went back to Frederica, leaving outposts to watch the Spaniards. There he found that his provisions were running low, and he knew that no more could be brought in since the enemy blocked the sound. He told the people, however, that if they had to abandon their settlement they could escape through Alligators Creek and the canal that had been cut through Generals Island, and he assured his little army of 800 men that they were more than a match for the whole Spanish expedition. Presently Spanish galleys came up the river; but Indians, hid in the long grasses, prevented the soldiers from landing. When they approached the town the batteries opened such a hot fire that the galleys fled down-stream much faster than they had come up. English prisoners, escaping from the Spaniards, began to bring word that the enemy were much discouraged. Many Spaniards had fallen sick, and the soldiers from Cuba were wrangling with the men from Florida. Oglethorpe therefore planned a surprise for the enemy and marched to within a mile of their camp. He was about to attack when one of his soldiers, a Frenchman who had volunteered but was in reality a spy, fired his gun and ran from the general's ranks. The Frenchman was not caught, and the general knew that he would tell the Spaniards how few English soldiers there were. So Oglethorpe tried a trick of his own, hoping to make the Frenchman appear to be a double spy. He hired a Spanish prisoner to carry a letter to the spy. "The letter was in French," Oglethorpe later said, "as if from a friend, telling him that he had received the money, and would strive to make the Spaniards believe the English were very weak; that he should undertake to pilot their boats and galleys, and then bring them into the woods where the hidden batteries were. That if he could bring about all this, he should have double the reward, and that the French deserters should have all that had been promised them. "The Spanish prisoner got into their camp," Oglethorpe said, "and was immediately carried before the general. He was asked how he escaped and whether he had any letters; but denying this, was searched and the letter found. And he, upon being pardoned, confessed that he had received money to carry it to the Frenchman, for the letter was not directed. The Frenchman, of course, denied knowing anything of the contents of the letter, or having received any money or had any correspondence with me. Notwithstanding which, a council of war was held and they decided the Frenchman a double spy, but the general would not suffer him to be executed, having been employed by himself."