There are some interesting things in the historical record.
SOURCE: Congressional Globe, Senate, 39th Congress, 1st Session, July 28, 1866
Pages 4291-2
ASSASSINATION REWARDS
The Senate, as in Committe of the Whole, resumed the consideration of House bill No. 801, authorizing the payment of the rewards offered by the President of the United States, &c.
Mr. DAVIS. I should like some Senator to give the Senate some assurance that Abraham Lincoln's murderer was in fact killed. I have never seen myself any satisfactory evidence that Booth was killed.
Mr. HOWARD. In order to prove it demonstratively, perhaps we should be compelled to send for Boston Corbett, who shot him. I suppose the honorable Senator is speaking of Booth.
Mr. DAVIS. Yes.
Mr. JOHNSON. I submit to my friend from Kentucky that there are some things that we must take judicial notice of, just as well as that Julius Caesar is dead.
[nc - Senator Axel Foley: "Trust me."
Mr. DAVIS. I would rather have better testimony of the fact. I want it proved that Booth was in that barn; I cannot conceive, if he was in the barn, why he was not taken alive and brought to this city alive. I have never seen anybody or the evidence of anybody that identified Booth after he is said to have been killed. Why so much secrecy about it? Why was not his body brought up publicly to Washington city and exposed to the gaze of the multitude, that it might be identified? It may be that he is dead; but there is a mystery and a most inexplicable mystery to my mind about the whole affair. He may come back some of these days and murder somebody else.
I merely got up to make this suggestion. I supposed that some gentleman was in possession of facts going to show that Booth was identified. Identify Booth, and these men ought to have their reward, but I doubt whether this man Baker out to have anything. I believe he was a much bigger villain than any man he was pursuing. I do not doubt that at all; and I believe he is just such a man as to get up now a story of the capture of Booth when Booth had not been overtaken at all. If gentlemen will refer me to where I can get a narrative of facts to prove the identity of Booth, I will at my leisure read it with much interest. I want to be assured of the facts, not with a view to vote on this bill but with a view to the history of the transaction.
I do not see why, if Booth was in the barn, he should have been shot. He could have been captured just as well alive as dead. It would have been much more satisfactory to have brought him up here alive and to have inquired of him to reveal the whole transaction, to have implicated all who were guilty and to have exculpated all who were innocent. I do not see any reason why the matter had not taken that course. Bring his body up, carry it to the City Hall, expose it there to public gaze, let all who had seen him playing, all who associated with him on the stage or in the green room or the taverns and other public places, have had access to his body to have identified it. That was the way, where $100,000 was offered as a reward for capturing the man. I am certain I was as innocent of that murder as the child that is yet unborn; but I should have disliked to have $100,000 offered for me as an accomplice in that murder; it would have caused me to be hung or shot just as certain as fate.
Mr. CONNESS. That would be a big price.
Mr. DAVIS. I have no doubt that the honorable Senator from California could have had me captured or shot for $2.50 by some of his myrmidons.
Mr. ANTHONY. I am happy to relieve my friend from Kentucky by informing him that a small part of the skeleton of Booth is in the anatomical museum of the Surgeon General.
Mr. JOHNSON. Who knows that?
Mr. ANTHONY. I do not know how it is identified, but it is certified to be that.
Mr. SPRAGUE. I hope we shall have the question.
The bill was passed.
See LINK
BOSTON CORBETT
The Man They Called Sin Huevos
Boston Corbett became an evangelical Christian and began wearing his hair very long in the style of Jesus. To avoid the temptation of prostitutes, Corbett castrated himself with a pair of scissors.
He allegedly killed John Wilkes Booth.
After the war Corbett worked as a [mad] hatter in Connecticut and New Jersey. In 1878 he had a complete mental breakdown and lived in a dugout a few miles outside Concordia, Kansas.
Corbett was appointed assistant doorkeeper of the Kansas House of Representatives in Topeka. On 15th Febuary, 1887, he made an attempt to kill "heretics" in the legislature hall with a revolver. No one was hurt and after being arrested was declared insane and sent to the local asylum.
On 26th May, 1888, Boston Corbett escaped from the Topeka Asylum for the Insane. Except for a brief stay with Richard Thatcher, a man he had met while a prisoner at Andersonville during the Civil War, Corbett was never heard of again.
SOURCE: H. Donald Winkler, Lincoln and Booth, p. 188.
Corbett was a devout Methodist and an eccentric religious fanatic. Seven years earlier, after reciting passages from the Gospel of Matthew to a small gathering of prostitutes, Corbett castrated himself with a pair of scissors so that he would not succumb to sexual temptation. After his self-mutilation, he attended a prayer meeting, strolled for a while, ate a hearty dinner, then sought out a doctor for some sutures. Thus it is possible that the emotionally unbalanced trooper could have believed that God had instructed him to kill Booth.
SOURCE: Louis J. Weichmann, The True History of the Assassination of Abraham Lincoln and of the Conspiracy of 1865, p. 208
Colonel Conger gave Sergeant Corbett a stinging reprimand, and said to him, "why did you shoot without orders?" The Sergeant took the position of a soldier, saluted the Colonel, and with right hand pointed upward, said, "God Almighty ordered me to shoot." At this reply the Colonel mellowed in his manner, and said, "I guess He did," and then dropped the subject..
Blood on the Moon, Edward Steers, Jr., 2001, pp. 262-4
Stanton's order calling for an autopsy and identification of the body is contained in a letter that he and Navy Secretary Welles jointly sent to the commandant of the Navy Yard who had asked Stanton what should be done with the body:
You will permit surgeon General Barnes and his assistant, accompanied by Judge Advocate Genl Holt, Hon. John A. Bingham, Special Judge Advocate, Major [Thomas] Eckert, Wm. [Luther] Baker, Lieut. Col. Conger, Chas. Dawson, J. L. Smith, [Alexander] Gardiner [sic] (photographer) + assistant, to go on board the Montauk and see the body of John Wilkes Booth.Immediately after the Surgeon General has made his autopsy, you will have the body placed in a strong box, and deliver it to the charge of Col. Baker -- the box being carefully sealed.
* * *
Alexander Gardner, who had left Mathew Brady to become an independent photographer, was allowed to board the Montauk with an assistant, Timothy O'Sullivan, and photograph the body. Gardner returned to his studios accompanied by a military guard who had instruction to confiscate the photographic plate and subsequent print and bring them directly to Stanton. It is not clear why the government should have allowed pictures to be taken or what the photographs would prove that eyewitness testimony would not prove. Presumably Stanton wanted to personally see the corpse of Booth to satisfy himself that Booth had been killed, But photographing the body is one thing, taking a close-up photograph of the initials was another. It would be virtually impossible to photograph the initials so that they would be legible in a photograph and still see the rest of the body including the face. Rather than rely on photographic evidence that is subject to alteration, there are several witnesses who described the intials on Booth's hand and those seen on the corpse.
Gee, guess what? The witnesses were selected by the War Department. They do not include family or friends of Booth, both readily available. Arrested accomplices were also aboard the ship. They were not invited to the identification party either. A photographer was invited and photographed the body. Stanton confiscated all photographic evidence. And for Steers, "it is not clear why the government should have allowed pictures to be taken or what the photographs would prove that eyewitness testimony would not prove." Indeed, "rather than rely on photographic evidence that is subject to alteration, there are several witnesses...." Eyewitnesses selected by Stanton, no less.
Forgive me, but I will take the pictures, thank you very much. Oh, wait a minute. What pictures? Have you seen any pictures of that body? All photographic evidence was immediately hand-carried to Secretary Stanton and, along with half of the Booth diary, vanished.