After Cassidy's release from prison, he and Lay organized the Wild Bunch gang, which began the most successful train-robbing career in history.

[citation needed] The gang would commit their robberies, split up, and then head in several different directions, meeting some time later in the Hole-in-the-Wall hideout in Wyoming.

[citation needed] In March 1912, Kilpatrick boarded a Southern Pacific Express train near Sanderson, Texas, alongside a former inmate whom he had befriended.

Attempting a robbery, Kilpatrick held up the express messenger, David Trousdale, in the Wells Fargo baggage and mail car.

While Kilpatrick looted the safe and any other valuables he could find, Trousdale managed to hide an ice mallet underneath the back of his jacket.