John G. Nicolay, The Outbreak of Rebellion

So far everything had gone as harmlessly as if the affair were merely a gala parade; but now a most deplorable occurrence succeeded. The march, the halt, and the capture greatly excited a vast crowd which the occasion drew together; and scarcely had the homeward march with the prisoners begun, when the troops were assailed by secession rowdies with abusive language, stones, missiles, and finally a pistol shot or two. This last provoked a return volley without orders from one or two companies, by which, and the desultory shots succeeding, fifteen to twenty innocent bystanders and several soldiers were instantly killed. The untoward incident caused a dangerous ferment in the city, but the courageous efforts of the police prevented a general riot.

The telegraphic news of the capture of Camp Jackson threw the Governor's revolutionary cabal and disloyal legislature sitting at Jefferson City into the utmost consternation. The Governor immediately sent out and caused a bridge on the railroad from St. Louis to be burned, to prevent any sudden descent by Lyon upon the capital; and during the afternoon and night, the Legislature in secret session rushed through several acts specially designed to promote rebellion, which they had before been concocting with more circumspection. A few days later, a military bill, virtually making the Governor an irresponsible military dictator, was formally passed; and having thus, as the conspirators thought, made all necessary legal preparations, the session was finally adjourned on May 15th.

General Harney, the ranking officer in the Department of the West, who had been temporarily called away, returned to St. Louis the day after the Camp Jackson affair, thus superseding Lyon in command. It must be explained that events, and particularly antecedent conditions, had most unfortunately