An important incident at Black Jack was the failure of the deputy United States marshal, Wm. J. Preston, to arrest the Browns. He had warrants for their arrest for the murders on the Pottawatomie, and came with Sumner to accomplish it. The Colonel notified Brown that they would be served in his presence, but when ordered by Sumner to proceed, the marshal said: "I do not recognize any one for whom I have warrants," to which the Colonel replied: "Then what are you here for?"[164] A man of Brown's years and experience and courage is a dangerous animal when thus situated. That a tragedy was impending is more than probable. At any rate, Preston quailed under the hostile look which Brown fixed upon him. What would have happened if the marshal had attempted to make the arrests, none can say, but Preston decided not to mix up in a tragedy. Another incident in the affair of historical importance was the presence of John E. Cook, as a guest in Brown's camp. None of Brown's biographers has referred to this incident, but the fact appears in Cook's confession heretofore quoted from. It will be difficult for anyone to account for Cook's presence there, at that psychological moment, upon any hypothesis other than that he was there by virtue of an invitation from Brown, or other notice or understanding with him. It follows, presumptively, that this was not the first time they had met, and that they were mutually interested in the problem which Brown had under consideration: how to get away, safely, with the horses and mules which he had taken from Pate. The final clause of the last sentence in the "Articles of Surrender," foreshadows the possibility, or probability, that some of the horses might be missing later on, and gives credit to the suspicion, or assumption, that Cook had come to the camp to run the stock off north and turn it into money, as had been done with the Pottawatomie horses. That the horses and mules herein were not run off immediately, and disposed of, was doubtless due to the negotiations that were pending for the liberation of Brown's sons. He probably thought that a theft of the horses would be construed as a violation of the terms of the surrender, and might prevent the exchange of prisoners that he hoped to effect. But whatever his hopes and his plans may have been, they were all dissipated and broken up by a fly that unexpectedly dropped into the ointment of his calculations: the arrival upon the scene of Sumner, with his cavalry. He spoiled everything. First he made Brown give back to Pate's men all the property he had taken from them, or as much of it as was visible, and then peremptorily ordered all the combatants to disband and return to their homes.