Below is the request sent to then FBI Director, J. Edgar Hoover, in an effort to obtain the documents.

Transcript
City of Miami-Florida
November 17, 1939
Mr. John Edgar Hoover, Director,
Federal Bureau of Investigation,
Washington,D.C.
Dear Director:
It is apparent from all this sickening publicity that Al Capone is coming to Miami to reside in the near future.
You informed me personally one evening at the Willard hotel that Capone is definitely afflicted with a brain disorder known as 'Paresis'.
I am going to endeavor to institute lunacy proceedings against Capone, and in order to meet with any degree of success, I would have to obtain a copy of the government doctor's diagnosis, relative to this condition, which if true will give me sufficient material to prove him a public menace.
I realize that the Federal Bureau of Prisons will not voluntarily release such a statement, and I seek your advice as to what procedure I should adopt to obtain such a document.
Your co-operation in this matter will be greatly appreciated and treated with the utmost confidence.
Respectfully yours,
(Signed)
James O. Barker, Lieut. Dets.,
Miami Police Dept.
Residence.
2271 S.W.20th St.
Phone 46-413