Louis J. Weichmann, the boarder at Mary Surratt’s house who testified against her, went on to work as a newspaper reporter, worked in a customs house and opened a business college.
After he testified against Mary Surratt in 1865, Secretary of War William Stanton helped him get a job at the Philadelphia customs house.
He was obliged to return to Washington to testify at the trial of John H. Surratt Jr. in 1867.
After he testified against his former friend, Weichmann received threatening letters and was put under the protection of government detectives.
He eventually moved to Anderson, Ind., where his brother was a Catholic priest. He opened a business college.
Before he died at age 60, a nervous and broken man, Weichmann signed a statement that all of the evidence he gave at the trials was absolutely true.
Source: Reveille in Washington by Margaret Leech