The actions of the pair did not suit Captain Moore in the least, and that night he took it upon himself to watch them more closely than ever.
In the darkness he saw Bicker make his way to the stable, and to that spot, a little later, Drossdell followed.
"Something is in the wind, and I'm going to find out what it is," he mused, and watching his opportunity he passed into the stable unobserved.
At first he could hear nothing but the movements of the horses, but presently came a low murmur from one corner of the loft.
Cautiously the young officer climbed the ladder and stepped into the hay.
Here he could hear the conversation between Bicker and Drossdell quite plainly.
"They never suspected the butter," he heard Bicker say. "It tastes a little strong, but they would rather have it that way than have none, and the same way with the condensed milk."
"When shall we give the signal to the boys?" came from Drossdell.
"Not yet. There will be more of them sick by to-morrow night," replied Bicker.
More of the same sort of talk followed, until the young captain became fully convinced that Bicker and Drossdell were in league with the desperadoes, and that they had been using some drugs in the butter, milk, and other articles consumed at the fort, in order to make the soldiers sick.