The plot was discovered during an investigation of the Bye Plot in which Sir George Brooke, the brother of Lord Cobham, was implicated.1 The effort of examining the evidence gathered from suspects questioned in the far-fetched Bye Plot fell to William Waad. He teased out the "main" or serious plot, as he saw it and involving the highly placed Raleigh, from the rest of the "bye" plot; and presented his findings to Sir Robert Cecil and the Privy Council.2
Cobham and Raleigh were both imprisoned in the Tower of London as was Sir Griffin Markham. Raleigh was released after thirteen years, but was eventually executed in 1618. The sick Cobham was released in the same year, dying some months later.
"Brooke, George" . Dictionary of National Biography. London: Smith, Elder & Co. 1885–1900. https://en.wikisource.org/wiki/Dictionary_of_National_Biography,_1885-1900/Brooke,_George ↩
Fiona Bengtsen, Sir William Waad, Lieutenant of the Tower, and the Gunpowder Plot (2005), p. 27; Google Books. https://books.google.com/books?id=meTCjNCYmsIC&pg=27 ↩