The Supreme Court Building is constructed on the very ground of the Old Capitol buidling that became the emegency Old Capitol Prison for traitors in the Spring of 1861.
For the next four years, Lincoln, Seward, Stanton and the Secret Service Chief Lafayette Baker grabbed whomever they wanted without a warrant, threw them into Old Capitol's dreary rooms, and forgot about habeas coprus, indictments, trials for as long as was useful.
Lafayette Baker's motto on his badge was "Death to Traitors."
When some several of those very same traitors conspired to murder Lincoln and Seward in April, 1865, Baker assigned his cousin to track them down and bring them to the noose. Booth likely shot himself, or was shot; but the Bakers bagged anyone they could argue was attached to the plot and threw them into a hastily constructed court in May, 1865, where the Attorney General and Provost Marshall General engineered a speedy conviction. Some few of the culprits were hanged at Old Capitol Prison.