Thomas F. Harney

Thomas F. Harney was a Confederate explosives expert, who was arrested by the Union Army in the final days of the US Civil War - seemingly en route to bomb the White House.

On March 22, 1865, Booth, Sarah Slater and colleagues are meeting at the St Nicholas Hotel in NYC where it's learned the White House has an underground entrance beneath the cabinet offices - though they have no explosives or expertise to use that information. On March 25 Sarah is at the Surratt boardinghouse and tavern, though her escort Augustus Howell has just been arrested - John Surratt accompanies her to meet Judah Benjamin on March 29 in Richmond, where he registers a room in the name Harry Sherman. Benjamin takes out $1500 in gold, giving $200 to Surratt as payment for getting the remaining Montreal money, $650,000, couriered safely to France or England.

At the same time, Gnl Gabriel Rains of the Confederate Naval Ordnance Bureau receives a message the same day to send a demolitions expert to Virginia to meet with Mosby for insertion into DC. Harney was rapidly dispatched toward Richmond, from his work as a "torpedo planter" working on the CSS Hunley and later developments, but on April 2, 1865, the city was evacuated. Mosby, Sarah Slater from Montreal and John Surratt were among those scattering - Harney took a train to Gordonsville where he is believed to have met Major Cornelius Boyle to pass a further message to Mosby. Boyle then gave Harney a horse and a guide believed to be Thomas Franklin Summers - who would help him bring his explosive payload to the White House.[1] During those same days, Mosby sent his personal friend Capt Robert S. Walker to meet with Boyle "to learn the true state of affairs".[2]