New Eyewitness Account?

[Steve]

With all this debate about who was really at the box before Lincoln's body was moved (Laura Keene, etc), it occurs to me that I haven't seen any account of what happened by Maj. James Potter, the Army paymaster who escorted Mary Lincoln from the box to Peterson House at the request of Maj. Rathbone. He's mentioned in Rathbone's statements, the newspaper accounts, etc. But I can't find any testimony, affidavits, later accounts written by him, or later newspaper stories about him that give his version of what happened. I think he was just outside the box and not in it, but he would've seen if Keene was admitted to box and would definitely know if she walked with Mary to Peterson House. The closest thing I could find to an account by him is this book about Kingston, Rhode Island mentioning that his daughter mentioned it:

https://books.google.com/books?id=iqZ5wX...on&f=false

Does anybody know if there is a surviving Potter account?