What was the Marais des Cygnes Massacre? How was Emory Bussey involved?

The Marais des Cygnes massacre was an incident, in which, "a band of armed Missouri border ruffians had captured eleven Free State men, marched them to a gulch only eleven miles from the Bussey home, lined them up and fired a volley, killing five."

I see no evidence of Emory being involved, do you have a chapter number for your question?