Salon.com has some of the Facebook messages sent between Spc. Adam Winfield—one of the five soldiers accused of killing Afghan citizens, seemingly for sport—and his father. The Facebook messages pertain to the first killing and they're pretty heartbreaking.

Via Salon.com:

Winfield wrote his father, Chris, on Feb. 14 about his concern that two members of his platoon had the previous month murdered "some innocent guy about my age just farming." The correspondence from that day illustrates the young soldier's horror at the murder, and also reveals a shocking indifference about the killing among the other troops in his platoon.

"Well, it was two guys who did it actually killed the dude (sic) but the whole platoon knew about it," Winfield wrote to his father. "Theres (sic) no one in this platoon that agrees this is wrong."

Chris—Winfield's father—says that after receiving the emails, he contacted military officials and warned them about the killing. Today, the army said that they're taking his claims seriously and investigating, but they won't release the name of the sergeant the elder Winfield spoke with or that man's recollection of their conversation. But here's Winfield's recollection:

Winfield, of Cape Coral, Fla., said he had a 12-minute conversation with a sergeant who told him that unless his son was willing to come forward in Afghanistan, he should keep his head down until the deployment ended, when his claims could be investigated.

Winfield also said he left voice-mail messages at a Defense Department hot line and at the base's criminal investigations division. Collins said investigators have uncovered no evidence of the voice-mail messages.

By the time suspects were arrested in May, three months after Winfield's alleged warning, two more civilians had been killed. Five soldiers have been charged in the killings - including Spc. Winfield.

Every detail that comes out adds another horrible angle to this depressing story.