Conversation so far:
What connection does Osceola have to relics?
Dr. Frederick Weedon was alone with the body and cut off Osceola's head.
Was Benjamin Strobel successful doing the death mask of Osceola?
An acquaintance of Pitcairn  Morrison, Dr. Benjamin Strobel made a plaster cast of Osceola's face and upper torso.
What happened after Osceola's death mask was done?
The process of pulling the first mold, which was soon displayed in the window of a Charleston drugstore, destroyed the original cast.

Question: What did the army officer did with it?
Self-contained rewrite: What did Captain Pitcairn Morrison do with Osceola's death mask?