He stated to them, when they gathered, the necessity of at once capturing the camp, and his determination to do so and hold all in it as prisoners of war. Blair and Witzig warmly approved this; Filley and Broadhead finally acquiesced, while How and Glover were opposed to both the manner and time and wanted a writ of replevin served by the United States Marshal. If Gen. Frost refused to respect this, Lyon could then go to his assistance. 73 Lyon yielded so far as to allow Glover to get out the writ of replevin, but he was not disposed to dally long with that subterfuge, and his line of battle would not be far behind the Marshal. Even before he went out to the camp he had sent an Aid to procure 36 horses for his batteries from the leading livery stables in the city, because he feared that Maj. McKinstry, the Chief Quartermaster of the Department, could not be trusted; a doubt which seems to have been well founded, for Maj. McKinstry afterwards refused to pay for the horses until he was compelled to do so by a peremptory order from Lyon. The Secessionist spies were as vigilant and successful as those of the Unionists, and Gen. Frost was promptly informed of the designs upon him, whereupon on the morning of the fateful May 10 he dispatched Col. Bowen, his Chief of Staff, with the following letter to Gen. Lyon: Headquarters, Camp Jackson, Missouri Militia, May 10, 1861. Capt. N. Lyon, Commanding United States troops in and about St. Louis Arsenal. Sir: I am constantly in receipt of information that you contemplate an attack upon my camp. Whilst I understand you are impressed with the idea that an attack upon the Arsenal and the United States troops is intended on the part of the Militia of Missouri, I am greatly at a loss to know what could justify you in attacking: citizens of the United States, who are in the lawful performance of duties devolving upon them, under the Constitution, in organizing and instructing the Militia of the State in obedience to her laws, and therefore have been disposed to doubt the correctness of the information I have received.