A detailed account of the evidence is given on this link
1921 Apr 18 . Michael Tolan was arrested in county Mayo. He was detained in Ballina barracks. He was there until an order for his interment was procured.
1921 May 7. He was handed over to Auxiliaries of D Company ADRIC, for transportation to Galway. The Auxiliaries got there without their prisoner. He was not seen until his mutilated corpse was found in the bog at Shraheen . The remains had been taken to nearby League and buried in a plot marked "unknown.". The body had been mutilated, the feet had been hacked off and one of the arms had been wrenched from the body. Evidently it had remained in the bog for some time and the flesh had decomposed. Village dogs had also attacked it and further mutilated it. No one could identify the remains, and it was therefore placed in an unmarked pauper’s grave.
1921 Jul 11. A member of Dail Eireann inquired into Tolan's disappearance and was told: "I am informed by my Authorities that owing to the transfer & absence on sick leave of some of the members of the Auxiliary police force who are concerned in this case it has not been possible as yet to complete inquiries into the matter."
1921 Aug 10. P J Ruttledge, a solicitor in Ballina writes:- Dear Sir—I have been consulted by Mrs. Tolan, Shamble Street, Ballina, with reference to her son, Michael Tolan. Mrs. Tolan instructs me that her son was arrested by local Crown forces on the 18th of April last, and that after that date, although she made numerous inquiries at your barracks as to her son’s whereabouts, she failed to elicit any definite information about him. Since his arrest on the 18th April his mother has not heard from him. I would be obliged if you would furnish me with particulars of date of his removal from your barracks, the officer into whose charge he was handed over, and his destination, with a view to having him traced. Some serious, but I trust unfounded, reports have been circulated in this district about Tolan, which are causing uneasiness amongst the Republican forces, and lest this might interfere with the observance of the Truce I am forwarding statement in the matter to the Liaison Officer of Mayo and Galway Brigades—Commandant Staines—for investigation by him, and I will require the foregoing information to assist us
1921 Aug 14. L C Norrington DI, the local liaison officer replies: Reference your letter of the 10th inst., I have to inform you that Michael Tolan was in custody in Ballina Barracks from the 18th April until the 7th May. An order was granted by the Competent military Authority for his internment, and he was handed over on the latter date to an escort of Galway police, who returned to Galway that evening. I am informed that he did not arrive at the Galway internment camp, and am communicating with my authorities there, to obtain fuller information.
1921 Sep 27. WE White DI then writes to Ruttledge:-
Sir—Reference to your letter of 24th inst., re Michael Tolan. I am informed by my authorities that owing to the absence on sick leave of some of the Auxiliary Police Force who are concerned in the case, it is not been possible as yet to complete inquiries into the matter.—Yours faithfully,
1921 Oct 12 Tolan's brigade adjutant wrote Michael Collins for permission to disinter and examine this corpse.
1921 Nov 7 Ballina Herald reports "when the body of the man found in the bog was exhumed in the presence of a jury, the Deputy Coroner, Dr. McGuinness, and Dr. Crowley, T.D.; Dr. Ferran, T.D., and Dr. Madden. A post mortem examination was held, and the remains of all that was mortal of Michael Tolan was clearly and conclusively identified. The way in which he met his death is given in the horrifying story told by the medial gentlemen named. Two bullet wounds were found in the back of the head, one having an exit through the eye, and other through the cheek bone, four teeth which did not appear to have been extracted, were missing, and evidently broken off by a heavy blunt instrument; an arm was wrenched off, and in the chest penetrating to the back was a large wound as if inflicted by a bayonet. Such was the manner in which poor Tolan met his death."
1922 Feb 2, Report in Ballina Herald: At the Ballina Quarter Sessions, on Friday, before his Honour County Court Judge, Judge Doyle, K.C., Mrs. Anne Quigley, Mill Street, Ballina, applied for £5,000 compensation for the death of her son, Michael Tolan, an N.C.O. of the Intelligence Department of the I.R.A. After hearing the evidence ...his Honour, delivering that judgment, said he was satisfied that the body found was the body of this poor man. There was no doubt that he met with a violent death, and he must attribute that to those people in whose custody he was at the time, or at least to some of them. He did not attribute it to all of them, because he would be very sorry to think that even among the auxiliaries there was not a large number who were averse to those deeds. He had some difficulty in fixing the amount of compensation, but having regard to the applicant’s age, and to the fact that the man might marry, he thought £750 a fair award. He directed that it should be paid into that court--£650 of the amount to be allotted to the applicant herself and £100 to the credit of her grandchild.