Private First Class Bradley Manning is currently our nation’s most notorious whistleblower–the man many believe was behind Wikileak’s largest disclosures. Manning has remained a media mystery since his arrest in May of 2010, when he was put in solitary confinement. Only those who belong in his inner circle have heard his voice–until now. In the enclosed 4-minute audio interview above with journalist Denver Nicks, you’ll be able to hear the voice mail greeting Manning kept on his cell phone. Although the words Manning says are unremarkable, the tone of his voice is surprising and telling.

While researching the materials for his investigative report on Private Manning, Nicks came across an old Facebook post where Manning displayed his new cell phone number. By that point, Nicks had already immersed himself in Manning’s early life, and had spoken to a number of friends and colleagues from his home town in Crescent, Oklahoma. In the audio clip above, Nicks describes his reaction to hearing Manning’s voice for the first time, and suggests why it’s such an important part of understanding Manning.

Click here to read excerpts of Nick’s explosive new story, “Private Manning and the Making of Wikileaks: The Oklahoman Behind the Biggest Military Intelligence Leak Ever.”