Clement planned and led the first daylight peacetime armed bank robbery in U.S. history when he held up the Clay County Savings Association on February 13, 1866. The bank was run by the leading citizens of Clay County, who had just held a public meeting for their association. The governor posted a reward for Clement, but he and his band of outlaws conducted further robberies that year. On election day of 1866, Clement led his men to polling places in Lexington, Missouri, where they intimidated citizens and secured the election of a slate of candidates. A state militia unit entered the town shortly thereafter and killed Clement when he resisted arrest. It is uncertain when the Younger brothers joined the Clement gang. The first mention of their involvement came in 1868, when authorities identified Cole as a member of a gang that robbed Nimrod Long & Co., a bank in Russellville, Kentucky. Former guerrillas John Jarrett (Younger's brother-in-law), Arthur McCoy, and George and Oliver Shepard were also implicated. Oliver Shepard was killed resisting arrest and George was imprisoned. Once the more senior members of the gang had been killed, captured, or quit, its core thereafter consisted of the Younger brothers, Frank James, and Jesse James. 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 robberies 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 so-called James–Younger Gang. Two agents (Louis J. Lull and John Boyle) engaged John and Jim Younger in a gunfight on a Missouri road on March 17, 1874. Lull and John Younger were killed and Boyle and Jim Younger fled the scene. Another Pinkerton agent who pursued the James brothers, W. J. Whicher, was abducted and later found dead alongside a rural road in Jackson County, Missouri. Some Younger families changed their last names to Jungers to avoid a family association with the gangsters. The James and Younger brothers survived capture longer than most Western outlaws because of their strong support among former Confederates.