My sources tell me that he has been subjected to a series of long, arduous interrogations by CID investigators. Predictably, the CID guys are out to find just one thing: they want to know the identities of his two or three NCO corroborators. The CID folks are apparently indifferent to the accounts of wrongdoing - telling him repeatedly not to waste their time with his stories. Fishback knows if he gives their identities up, these folks will also be destroyed - so he's keeping his silence, so far.
The investigators imply that he failed to report abuses, so he may be charged, or that he is peddling falsehoods and will be charged for that. They tell him his career in the Army is over. Meanwhile the peer pressure on him is enormous. I'm reliably told that he has been subjected to an unending stream of threats and acts of intimidation from fellow officers. He is accused of betraying the Army, and betraying his unit by bringing it into disrepute. His motives are challenged. He is accused of siding with the enemy and working for their cause. And it goes on and on.
The New York Times has more on the pressure against Fishback to speak out: "[W]hen he took his complaints to his immediate superiors, Captain Fishback said his company commander cautioned him to 'remember the honor of the unit is at stake.' He said his battalion commander expressed no particular alarm."