In fact, it was generally believed that those Indians who gathered about the entrance of the fort, prepared to rush in the moment the last men passed out, took no part in the later events of the day, being fully occupied in their work of plundering and cattle-killing. John Wentworth in one of his lectures on the subject went further, and declared that the Indians who had lived a long time in the immediate vicinity of the fort were friendly to the whites and "did their best to pacify the numerous warriors who flocked here from the more distant hunting grounds."

The column had not proceeded very far on its course before it was noticed that the Potawatami escort was diverging from the direction in which both columns started out and that at the distance of a mile from the fort there was a considerable distance between them.

A range of sand-hills and sand-banks of no great height skirted the shore dividing the sandy beach from the prairie beyond them. Among these sand-hills were a few trees and bushes supporting a precarious existence. Westward of this range of sand-hills which began to rise about a mile from the fort the Indians continued their course and were soon lost to view.

Suddenly, far in the advance, Captain Wells was seen to turn his horse and ride furiously back along the marching men, who quickly came to a halt. Wells was swinging his hat in a circle around his head, which meant in the sign language of the frontier, "We are surrounded by Indians!" As he approached the commanding officer he shouted, "They are about to attack us; form instantly and charge upon them." The Potawatami escort had in fact become the attacking party, choosing to murder the whites rather than join in looting the fort.

The Indians could now be seen in great numbers coming into view from behind the mounds of sand, their heads bobbing up and down "like turtles out of the water." The troops were promptly formed and they had no sooner taken position than the Indians began firing upon them with deadly effect, the first victim being a veteran of seventy years of age.

After firing one round the troops charged up the slopes of the sand-hills, driving the Indians from the position. However, they scattered in both directions and presently began to envelop the flanks of the line according to the usual practice in savage warfare. At this juncture the mounted Miamis would have been of the greatest service in preventing such a manœuvre, but they had all fled across the prairie after the first shot was fired, quickly disappeared in the distance, and were seen no more.

Captain Heald, in a letter written a few weeks after the event, said:

The situation of the country rendered it necessary for us to take the beach, with the lake on our left, and a high sand-bank on our right, at about one hundred yards' distance. We had proceeded about a mile and a half when it was discovered that the Indians were prepared to attack us from behind the bank. I immediately marched up with the company to the top of the bank when the action commenced; after firing one round we charged, and the Indians gave way in front and joined those on our flanks.

The horses upon which Mrs. Heald and Mrs. Helm were riding became almost unmanageable after the firing had begun. The explosion of a charge in an old flint lock musket was a terrific outburst of noise. It produced a volume of sound which we can scarcely realize when comparing it with the report of a service rifle in use at the present day. It was little wonder that the horses pranced and bounded when these thundering volleys were heard.

Mrs. Helm said that she drew off a little and gazing upon her husband (Lieutenant Helm) and her father (Mr. Kinzie), whom, although he was her step-father, she was always fond of calling father, she saw that they both were yet unharmed. But she felt that as for herself her hour had come, and she endeavored to forget those she loved, and to prepare herself for her approaching fate.