"And he looked around the room and looked at me, and he says, 'You just don't know who you can trust anymore, Darb, do you?' And I thought he knew. But then he moved on and he came out of the room, you know, we started talking and I realized he didn't know."
The New Yorker's Seymour Hersh originally broke the story and included Darby's name in the article. Even so, Darby said he retained his anonymity because "no one on base read that magazine." Everyone would learn of his involvement soon enough, however, thanks to Secretary of Defense Donald Rumsfeld.
Darby and his platoon were watching a congressional hearing on the mess hall TV when Rumsfeld inadvertently blew the whistle-blower's cover.
"There are many who did their duty professionally. First Spc. Joseph Darby, who alerted the proper authorities that abuses were occurring," Rumsfeld said.
"And I was actually less than 10 feet from the TV when Donald Rumsfeld mentioned my name. And the two soldiers I was sitting with, you know, said, 'We need to leave,'" Darby said. "But it was less than three hours before e-mails and phone calls home, everyone in the unit knew who I was, that I had done it."
Darby said 90 percent of the soldiers he interacted with said he had done a good thing.
Others sad he was a traitor.
In his hometown, the ratio swung the other way. Darby said that only about 10 percent of people supported him.
"It was about 90 percent didn't agree with what I did, including some of my family, and 10 percent supported me, but very few would do it openly," he said.
Threats against his wife and mother drove him and his family from their home in Jenners, Pa.
He lives in exile now, weary from the ordeal, but remains steadfast in his knowledge of right and wrong.
He said he would do it all again.
"It had to be done," he said.