Some of the items recovered from Booth’s body upon his death at the Garrett farm. A few of the items pictured (the keys and whistle) are questionable and may not have been recovered from Booth’s body.
Image Source: LOC
Booth’s belongings
Discovering the Conspiracy
LincolnConspirators.com 
The whistle’s a link to others conspirators, signaling with it was heard by people around the theatre. But what happened to the diamond stick pin that Booth spoke of giving to Seward’s maid where Lewis Payne went with a bowie knife and an unserviceable Spiller & Burr. Why? As one of Quantrill’s raiders surely he knew firearms well enough to know this, but why?