Agent Enfield surveyed the scene, keeping his opinions to himself. Major Whitside brought his horse beside Enfield's and looked through his binoculars.
"Not too many of them," Enfield muttered, half to himself.
"Enough to be a hell of a problem," Whitside replied. "I've ordered our troops to begin disarming them."
"Of course," Enfield said. Whitside called them their troops, believing his orders that said that Enfield was a colonel brought in to advise on Indian warfare. The Initiative had forged everything; correspondences between Whitside and the commanding general, credentials from the War Department, fake orders. The American Secure Containment Initiative may have worked mostly outside of government and military circles, but they were rapidly becoming experts in threading their way through bureaucratic channels undetected. All that skill, all those lies, all to protect the nation from threats nobody else could know about. A noble cause.
Enfield spat in the ground. He had trouble accepting this as "noble."
"Do you think they're likely to make a fuss, Colonel?" Whitside asked.
Of course they are, Enfield thought, that's the point. "Not too likely, not if they're smart," he lied. "But keep the Hotchkiss guns around them just in case."
"Yes sir," Whitside replied, then rode off down to the encampment. Enfield put his binoculars back up to his head and looked again. He owed them that.
Three hundred fifty Lakota Indians. One hundred twenty of them men, the rest women and children. Many of them followers of the person known to the Institute as Entity 1887-016. If "person" was the correct word. The ASCI had only recently begun investigating beings like 016, beings capable of changing the world around them, capable of twisting and bending nature itself. The ASCI's counterpart in the German Empire referred to them as "Daseinkrummeren". Existence warpers. He hoped a catchier term would catch on eventually.
Enfield had been hoping there was some other way to detain him. He pulled 016's file out of a pocket of his jacket, the file he had written. He had compiled all of the information they had gathered on him. Then, when his superiors told him what they needed him to do, he reread everything, trying to find a loophole. He even tried to find a way that the warper might be more powerful than they thought, maybe even immortal. But all evidence pointed towards this conclusion, this method. Sitting down there in the valley. Enfield reread his own words.

Entity 1887-016 possesses two principal anomalous abilities. 016 is capable first of performing a ritual dance, identified here as 1887-016A, that renders individuals around him increasingly susceptible to suggestion, particularly advice and ideas presented by 016. Second, E1887-016 gains the ability to cause or prevent the motion of inanimate objects, given that he is in close proximity to a number of individuals (specific requirements unknown at this time) that are compromised by his first ability. In short, 016 is capable of moving or stopping objects without touching them so long as he is surrounded by people who believe he is capable of doing so.
These two abilities feed into one another; people convinced of the legitimacy of his "medicine" allow him to perform minor parlor tricks, increasing people's faith in him and strengthening his abilities. Rumors suggest that 016 is capable of much more than this, though this is not known for certain by ASCI at this time.
Given the dependence of 016 on his followers, it is believed that

Raised voices from the valley below. One of the Lakota was doing 016's dance, the Ghost Dance. The entity had started the rumor that once enough people began doing the Ghost Dance, their gods would wipe the white man from the continent and return the land to its previous pristine beauty. Enfield didn't know if he had also started the rumor that wearing special white shirts would make you bulletproof, but it wouldn't surprise him. If 016 were here now, his abilities would probably allow him to stop quite a few bullets. Parlor tricks like that were what gained him a following in the first place. Nobody knew what he was really capable of once enough people believed in him, but it wasn't likely to be pretty.
The Lakota kept dancing, half from belief, half from protest. Enfield could tell the difference; he had spent enough time around Sioux and Comanches to know the particular veiled hate of occupied peoples. He had no idea who at headquarters had drawn up this plan, but whoever it was had that same insight that he did. Maybe less of a conscience, but that could be what it took to do this job. God knows Enfield couldn't have done it. God only knew how much longer he could keep doing jobs like this.
Here it came. The disarming, the dance, then…
The report from the rifle sounded so small from so high above. Enfield knew when he read the plan that disarming an angry group of Indians frequently led to some kind of violence. Somebody wouldn't want to give up their gun, a scuffle ensues, and then a gun goes off. Automatic weapons around the encampment, plus a regiment already on edge from chasing Indian tribes all around the plains, and what happened next was inevitable. The Hotchkiss guns started pouring bullets into the encampment. Those Lakota not yet disarmed tried to shoot back, even killed a few of the soldiers. Enfield felt no particular loyalty to one side or the other. He was sickened by the murder happening below, and moreover, by the fact that he was responsible for it.
But there was no other way. He was sure of it. 1887-016 gained power from having people believe in him. The only way to capture him was to shatter the faith of his followers. The only way to keep him from becoming more powerful was to take away the only thing these people had to believe in.
The shooting stopped. Over a hundred dead; Enfield could see that. Mostly women and children. Soldiers were walking around the encampment laughing and pointing at the bodies. Enfield knew many of them just thought of this as a game, and that most of them barely thought of the Indians as people in the first place. They could enjoy this. Plenty of "researchers" back at the Institute would probably enjoy hearing about this too. Enfield was sick thinking about it.
But their faith was gone. However horrible this day was, 1887-016 was exposed now, powerless. Enfield didn't know where he was, but he swore, there and then, that 016 wouldn't get the chance to gain a following again. Not that that was likely. Not after this.
Enfield put his binoculars back into his coat pocket, turned his horse around, and rode away from Wounded Knee Creek.