The Missouri Bushwackers ventured into kansas in retaliation as Walley and his men caused a two-story building located between 14th and 15th streets on Grand Avenue to collapse and kill nearly 25 women who were in custody there for providing assistance to Missouri bushwackers in some earlier raids into Kansas. Two of these were cousins, and three were Cole's sisters. The first story of the building was a grocery store but the grocer managed to get all of his inventory out of the place just before it collapsed.
Younger later claimed he left the bushwhacker ranks to enlist in the Confederate Army, and was sent to California on a recruiting mission. He returned after the Southern defeat to find Missouri under the rule of a militant faction of Unionists, the Radicals, who soon took over the regular Republican Party in the state. In the closing days of the war, the Radicals pushed through a new state constitution that barred Confederate sympathizers from voting, serving on juries, holding public office, preaching the gospel, or carrying out any number of public roles. The constitution also freed the slaves ahead of the ratification of the 13th Amendment to the U.S. Constitution. It enacted a number of reforms, but the restrictions on former Confederates proved divisive.
It is uncertain when Cole Younger and his brothers joined with this gang. The first mention of his involvement came in 1868, when authorities identified him as a member of a gang who robbed Nimrod Long & Co., a bank in Russellville, Kentucky. Jesse and Frank James were also suspected of taking part in that robbery, though Jesse would not be publicly identified as an outlaw until December 1869, after the robbery of a bank in Gallatin, Missouri, and the murder of the cashier, John W. Sheets. By that time, the more senior members of Clement's gang had been killed, captured, or quit, and its core would thereafter consist of the James and Younger brothers.
Witnesses repeatedly gave identifications that matched Cole Younger in robberies carried out over the next few years, as the outlaws robbed banks and stagecoaches in Missouri and Kentucky. On July 21, 1873, they turned to train robbery, derailing a locomotive and looting the express car on the Rock Island Railroad in Adair, Iowa. Younger and his brothers were also suspects in hold-ups of stage coaches, banks, and trains in Missouri, Kentucky, Kansas, and West Virginia.
Following the robbery of the Iron Mountain Railroad at Gad's Hill, Missouri, in 1874, the Pinkerton National Detective Agency began to pursue the James and Younger brothers. Two agents (Louis J. Lull and John Boyle) engaged John and Jim Younger in a gunfight on a Missouri road on March 17, 1874; Boyle fled the scene, and both John Younger and Lull were killed. Simultaneously, another agent who pursued the James brothers was abducted and later found dead alongside a rural road in Jackson County, Missouri.
The James and Younger brothers survived for so many years, in contrast to most Western outlaws, because of their strong support among former Confederates. Jesse James became the public face of the gang, appealing to the public in letters to the press (even press releases left behind at robberies), claiming to be the victim of vindictive Radical Republicans. The gang, and Jesse James in particular, became a major electoral campaign issue, as pro-Southern Democrats defended the outlaws and Republicans attacked them.
Cole, Jim and Bob pleaded guilty to their crimes to avoid being hanged. They were sentenced to life in prison at the Stillwater Prison at Stillwater on November 18, 1876. Frank and Jesse James fled to Nashville, Tennessee, where they lived peacefully for the next three years. In 1879, Jesse returned to a life of crime, ending in his murder on April 3, 1882, in Saint Joseph, Missouri. Frank James surrendered to Missouri Governor Thomas T. Crittenden on October 4, 1882. Eventually Frank James was acquitted, and lived quietly and peacefully thereafter.
Bob Younger died in Stillwater prison on September 16, 1889, of tuberculosis. Cole and Jim were paroled on July 10, 1901, with the help of the prison warden. Jim committed suicide in a hotel room in St Paul, Minnesota, over an unrequited love on October 19, 1902. Cole wrote a memoir that portrayed himself as a Confederate avenger more than an outlaw, admitting to only one crime, that at Northfield. He lectured and toured the south with Frank James in a wild west show, The Cole Younger and Frank James Wild West Company in 1903. On August 21, 1912, Cole declared that he had become a Christian and repented of his criminal past.