I believe his full name was John P. Gatewood, a rather sadistic, 19 year old, 6 ft., red head.
See page 652: http://books.google.com/books?id=8GsUAAAAYAAJ&pg=PA652&lpg=PA652&dq=Gatewood's+Guerrilla&source=bl&ots=GcMlNDYxF6&sig=L-tqTP_lXid_67paZnk8LMRy5Qs&hl=en&ei=Fb0tS9OePInusgOJyuHLBA&sa=X&oi=book_result&ct=result&resnum=10&ved=0CCsQ6AEwCTge#v=onepage&q=&f=false

Try a Goggle search Gatewood's Guerrilla