"Learning of the arrest, Boston's Vigilance Committee staged a mass protest meeting in Faneuil Hall on the evening of 26 May that abolitionists Wendell Phillips and Theodore Parker addressed. At its midpoint a militant faction, headed by Thomas W. Higginson, interrupted the proceedings to lead an armed attack on the Boston Court House to rescue the prisoner. The attack was repulsed, but a guard, specially deputized into federal service, was killed. To counter any more rescue attempts, the federal officials promptly assembled a posse; it consisted of approximately 180 soldiers and marines and 120 armed civilians known as the 'marshal's guard.'" David R. Maggines, American National Biography Online.
David R. Maggines, "Burns, Anthony," American National Biography Online, http://www.anb.org/articles/20/20-00129.html.