Actor John Wilkes Booth assassinated President Abraham Lincoln at the Ford Theatre in Washington,D.C. on April 14, 1865.
Wilkes had access to the theater because of his profession. He was a member of a famous theatrical family, although the least illustrious member: Junius Brutus Booth, a great English tragedian, emigrated to the United States in 1821 and had three sons, Junius Brutus Booth, Jr., John, and Edein Booth, a celebrated performer (often called the greatest American Hamlet of the 19th century) who became a theater entrepreneur, building the Booth Theater in 1869 — Broadway’s current Booth Theater is named after him.
Here are father and two sons performing in Julius Caesar, from left to right John, Edwin and Junius Sr.
John Wilkes Booth chose to murder the president during a performance of Our American Cousin, a farce by Tom Taylor about a boorish but honest American who travels to England to meet his aristocratic family. Booth hoped the gunshots would be drowned out by the laugh line to this highlighted passage:

The Night Lincoln Was Shot: Minute-by-Minute Backstage With John Wilkes Booth at Ford’s Theatre