But there were also many of these type of criminals also operating in the wake of Confederate forces. I've read much of similar Confederate atrocities associated with the passage of Wheeler's cavalry. But the problem with the Confederate civil oppression that I've been studying is that it was done under what passed for normal peaceful community life and was unrelated to military movements. For instance, the military requirements of the CSA did not need the existence of Captain Brown's systematic extortion of Unionists in the Cleveland Tennessee region.
I apologize for the long reply below, but I found some things I want to cite.
Like Sherman, Wheeler had unassociated groups of people following his troops too. Those groups apparently did pillage. Like Sherman’s troops, Wheeler’s cavalry lived off of foraging and people complained when their food stuffs were taken by either side. I don’t think Wheeler’s cavalry did any burning of homes like Sherman’s troops did. They destroyed things (bridges, railroads, etc.) and ran off stock and sometimes took stock that approaching Federal troops might use.
On the other hand, Sherman’s regular troops, not the bummers or Kilpatrick’s robbers, participated in wholesale burning of homes, villages, towns, and cities and the robbing of citizens in South Carolina. Consider the following from "A City Laid Waste; The Capture, Sack, and Destruction of the City of Columbia," by William Gilmore Simms, edited by David Aiken (an excellent book by the way). Simms was an eyewitness to the destruction and sacking of Columbia, South Carolina, and he published eyewitness accounts of the actions of Sherman’s troops in an 1865 Columbia newspaper just weeks after the city was burned. From page 61, originally from Simm's newspaper account:
Hardly had the [Union] troops reached the head of Main street, when the work of pillage was begun. Stores were broken open in the presence of thousands within the first hour of their arrival. The contents, when too cumbersome for the plunderers, were cast into the streets. Gold and silver, jewels and liquors, were eagerly sought. No attempt was made to arrest the burglars. The officers, soldiers, all, seemed to consider it a matter of course. And wo to him who carried a watch with gold chain pendant; or who wore a choice hat, or overcoat, or boots, or shoes. He was stripped by ready experts in the twinkling of an eye. It is computed that, from first to last, twelve hundred watches were transferred from the pockets of their owners to those of the robbers. Purses shared the same fate; nor was Confederate currency repudiated.
Sherman's troops had marched into town in an orderly fashion. Then when they were dismissed, wholesale robbery and plunder began and lasted the rest of the day and night. From page 64:
Sherman, at the head of his cavalry, traversed the streets everywhere – so did his officers – yet they saw nothing to rebuke or restrain. Subsequently, these officers were everywhere on foot, yet beheld nothing which required the imposition of authority. Robbery was going on at every corner – in every house – yet there was no censure, no punishment.
The huge fires that destroyed much of the city began at night started by Sherman's troops. They would rob a house of its valuable contents, then burn it. A few of Sherman’s sympathetic troops had earlier warned locals that this was coming. When local fire fighters attempted to put out fires, some of Sherman’s troops bayoneted and cut up the fire hoses.
Simms did report some plundering of commissary and quartermaster stores by Wheeler's cavalry and others just prior to the entry of Sherman's troops into Columbia.
I did find a report of apparent robbery by people under Wheeler’s command. From a Tennessee source about an 1863 raid by Wheeler: [Link]:
Following the surrender [of Union troops], according to Major Patterson, there occurred "the most brutal outrages on the part of the rebels ever known to any civilized war in America or elsewhere." The Major was shocked as the cavalrymen proceeded to outfit themselves in new clothes from head to foot, taking "boots, watch, pocket-book, money, and even finger-rings, or, in fact, anything that happened to please their fancy". Patterson, observing that General Wheeler had arrived on the scene, appealed to him directly to stop the pillaging. Wheeler only replied that he could not control his men, and that they would do as they pleased. Considering the dire condition of Forrest's men, whom most of these were, and their known reluctance to obey Wheeler's orders, the General probably stated the simple truth.
The book, “Those Damn Horse Soldiers” by George Walsh, reported (on page 234) that Patterson’s claim above was exaggerated.
Finally, here is a link to a National Parks Service site that says plundering by Confederate calvary became necessary for survival. [Link2] It mentions that Wheeler’s cavalry had not been resupplied for two years and that the clothes worn by Wheeler’s men were very tattered and that many did not have overcoats for the cold weather. It explains why they might have taken clothes from Union troops like in the 1863 raid above.
I don't know anything about the Captain Brown you mentioned. When and where was this and what exactly happened?