From the Richmond Whig, 4/20/1865, p. 5, c. 2
THE MINING OF THE LIBBY PRISON – An investigation of the basement of the Libby Prison since its occupation by the Federal military authorities, revealed the fact that the powder magazine planted there for the purpose of blowing up the prison in the event of the capture of Richmond by Dahlgren’s raiders, [next line illegible – MDG] plainly to be seen.