Captain Frey was taken prisoner at the battle of Gettysburg on 1 July 1863 and held in Libby Prison for eighteen months before being exchanged for Captain Gordon, a Confederate prisoner under sentence of death.
Kapten Frey ditawan pada pertempuran Gettysburg pada 1 Juli 1863 dan ditahan di Penjara Libby selama 18 bulan sebelum ditukar Kapten Gordon, seorang tawanan Konfederasi di bawah hukuman mati.