The article provides no evidence, outside of the speculation of four prison guards, that the mysterious building houses a prison. As you point out in your note, the guards "don't know for sure" what the building is used for. If they don't know, how can Horton build such an elaborate narrative about prisoners being transported to the facility alive and returned to Camp 1 dead on the evening of June 9, 2006? I consider this a flight of logic, and you should, too.
A just-published Horton dispatch, to which you refer, quotes a marine biologist who says he saw the mysterious structure in February 2004 while working on a project for the Pentagon. "[I]t looked a lot like the other prison camps I had seen," the biologist tells Horton, adding, "There didn't seem to be any windows in the facility."
If the building is a prison without windows, as the biologist surmises, how do we reconcile his description account with the account provided by Hickman, who tells Horton that "he heard a 'series of screams' from within the compound" one time that he stopped by. If the building has no windows, it's hard to imagine Hickman hearing a series of screams from inside. If guards kept doors ajar while they tortured the prisoners—or tortured prisoners outside—I suppose you could hear their screams. I'd love to know if Hickman, who says he was in earshot of the building, could tell us whether it has windows.
And seeing as you asked, I'm not calling anybody a liar. Do you think that the dozens of soldiers, sailors, and civilians who gave sworn testimony to NCIS investigators (large PDF, heavily redacted), testimony that contradicts Horton's findings, have perjured themselves? Are they liars?
Your note falls into a sinkhole of sophistry when you claim that Horton has no "clear theory" of how the prisoners died, and that he's only "suggesting" that the prisoners were tortured at the building he calls "Camp No." Are we reading the same piece? The Harper's headline places the word suicide in quotation marks ("The Guantánamo 'Suicides': A Camp Delta sergeant blows the whistle") to advance his idea that the prisoners did not take their own lives. Horton repeatedly refers to evidence or the possibility of a "cover-up," and he endorses the Seton Hall study (PDF) to claim that the "official story of the prisoners' deaths was full of unacknowledged contradictions, and the centerpiece of the report—a reconstruction of the events—was simply unbelievable."
What's this stuff about "conspiracy theory"? Others have called Horton's work conspiracy theory, but nowhere do I describe his work that way. Also, in using the words and phrases "seems to believe," "puts it," and "allegedly," I intended no mockery.
Since my piece appeared, several readers have called my attention to what they regard as a glaring error in Horton's feature, one that undermines his counter-narrative of the events of June 9, 2006. One of those readers was Dwight Sullivan, who served as the chief defense counsel in the Office of Military Commissions from August 2005 through August 2007. In that capacity, Sullivan drove from the naval station portion of Guantánamo Bay to the detention camps many times. Via e-mail he writes: