The FBI Agents present at the actual scene at the Conkel farm and the shooting of "Pretty Boy" Floyd were: SAC Melvin Purvis, Special Agents D. E. Hall, W. E. Hopton, and S. K. McKee.
In a memo detailing a call between Hoover and Purvis after the shooting, (Oct. 22, 1934 memo), Purvis stated he did not think Floyd fired any shots. Purvis advised that he and Hall had revolvers; Hopkin and McKee had .45 caliber Thompsons.
East Liverpool, Ohio police present were: Chief Hugh J. McDermott, Herman H. Roth, Chester C. Smith, and Glen G. Montgomery.
The 15 page Floyd report of SA S. K. McKee details what happened and who was present in the final hours of the shooting of Floyd. The report is about 14 meg in size and download times will be different depending on your system, etc.