You can read descriptions of what is in the courtroom murals here. My favorite one -- in the center of that picture (enlarge) -- shows:
...the trial of Chief Oshkosh of the Menominees for the slaying of a member of another tribe who had killed a Menominee in a hunting accident. It was shown that under Menominee custom, relatives of a slain member could kill his slayer. Judge James Duane Doty held that in this case territorial law did not apply:. . . it appears to me that it would be tyrannical and unjust to declare him, by implication, a malicious offender against rules which the same laws presume he could not have previously known...
Judge Doty acquitted Chief Oshkosh of the charge. They became friends.
This is the same legal issue depicted in the 1965 movie "Dingaka," which had a profound effect on me when I saw it as a teenager.
Here's another picture, of the courtroom, from behind the bench: