DENVER ( CBS4 ) - Three men are now suspected of installing devices at light - rail ticketing machines that steal consumers credit card information . The devices , called skimmers , were discovered before they could transmit any information . Investigators said nobodys information was compromised . Surveillance video shows two men who may have installed the devices into ticketing machines at the Mineral station in the south metro area . The devices were also found on ticket machines at the Dry Creek and County Line stops . ;