TACOMA, Wash. — One of the five Joint Base-Lewis McChord soldiers accused of killing civilians in Afghanistan has been placed in solitary confinement for his own protection, according to a CNN report.

Spc. Adam Winfield, 21, became a whistle-blower in the case when he told Army investigators that he alerted his father about the crimes being committed by his Stryker brigade squad early this year and also shared with him that he feared for his own life.

Winfield's father tried and failed to get the military to do something, apparently before the May killing in which Winfield allegedly played a role. The Army confirmed to The News Tribune last week that Christopher Winfield did talk to someone at Lewis-McChord on a general phone line in February, and said the incident is being investigated.

An Army spokeswoman would not tell CNN about the conditions under which the five defendants are being held, including whether they are able to communicate with each another.