Money (Symbol)
Money is symbolic of the moral conundrum many people faced in Chasing Lincoln's Killer. That is: what will (or should) people do for money and what will (or should) they do out of principle. For John Wilkes Booth and other Confederate sympathizers, people who act out of a desire for money are not as good as people who act out of principle.
John Wilkes Booth's Derringer (Motif)
This is the weapon that Booth used to assassinate President Abraham Lincoln. It is mentioned quite often in the book and is meant to underscore the depravity of Booth's act and to show how good of a leader and man Lincoln was.
The Confederacy (Symbol)
The Confederacy is symbolic of the ongoing divide going in the United States after the end of the Civil War. Despite the fact that General Robert E. Lee surrendered at Appomattox Courthouse weeks before, Booth and other Confederates still wanted the war to go on and wanted to cede from the Union. In other words, there was still a great divide in the country, which the Confederacy was symbolic of.
The Civil War (Symbol)
Quite simply, with the Civil War and the aforementioned Confederacy, Lincoln would very likely not have been shot. Beyond that, the Civil War was symbolic of not only the divide in the country, but symbolic of the cause John Wilkes Booth and other Confederates were fighting for -- that is, cession from the Union.
The Theater (Symbol)
The theater is an important aspect of the book. On the surface level, Lincoln was killed in Ford Theater by a theater veteran in Booth. More importantly, though, the theater was symbolic of Booth's arrogance that he thought he could survive during his escape by putting on an act and convincing other people to assist him.
