The 1881 history of Johnson County had a long, detailed write-up of the postwar "reign of terror" on pages 368-385. After the war this gang was composed of renegades, some of whom had been on either or both sides. A lot of Warrensburg men formed a vigilence committee and one, two, or three at a time disposed of these thieves and murderers who had practically taken control of the town and did whatever they pleased. Warrensburg was a true "wild west" town then. Those two you read about were lynched on a tree beside the train depot. By the way, the depot is still there, but I don't know if the tree remains.
Bruce