Deputy U.S. Marshal Virgil Earp assisted by his brother Wyatt and Sheriff's posse led by Behan attempted to track the Bisbee stage robbers. At the scene of the holdup, Wyatt discovered an unusual boot print left by someone wearing a custom-repaired boot heel. The Earps checked a shoe repair shop in Bisbee known to provide widened boot heels, and were able to link the boot print to Frank Stilwell. Stilwell had just arrived in Bisbee with Spence, his livery stable partner, and Virgil and Wyatt arrested both of them at the stable, for the stage robbery, on September 10. Cowboy friends provided Stilwell and Spence with an alibi, saying they were elsewhere during the robbery, and the state robbery charges were dropped.