Louis Weichmann

[Eva Elisabeth]

Another question - maybe Pamela has an answer? In his book, Weichmann quotes so many testimonies, letters, and other accounts, also such he hadn't personally witnessed. Where did he get all this from? Only about some he tells. Especially as for letters I wonder if all those quoted people shared the information voluntarily.
One example - he quotes an entire private letter John Surratt wrote to his cousin Bell Seaman on Feb.6, 1865. Did he secretly copy it somehow? Unless officially assigned this offended against data privacy.