The noted spy John Anthony Walker, Jr. (Johnny) served in "Niagara Falls" radio room from 1971 to 1974. It was during his time aboard "Niagara Falls" serving as communications officer and Classified Materials Systems (CMS) custodian that Walker had access to the various cryptographic machines (KW-7, KWR-37, KG-14, KY-8, and KL-47) providing the keys for nearly all of them to the KGB. Being a supply ship, "Niagara Falls" received classified messages about ships movements off Vietnam and in the South China Sea. In order to deliver this classified information to soviet contacts, it is believed by investigators, that CWO3 Walker made dead drops in ports of call including the Philippines, Hong Kong. Suspecting intelligence breach from the Niagara Falls, an intelligence operative was inserted as a junior Radioman in the mid-1970s to confirm but findings were inconclusive. Walker's accomplice Jerry Whitworth served aboard "Niagara Falls" as chief radioman and CMS custodian from 1978 to 1979.