The Pentagon's chief prosecutor for the Guantanamo military tribunals is leaving the job. Army Lt. Col. Robert Swann will succeed Army Col. Fred Borch, who leaves to take up a post at the Army's Judge Advocates General School. President Bush has approved holding trials for six detainees, among the hundreds being held but not charged, at Guantanamo Bay, Cuba. No trials have been held yet. NPR's Jackie Northam reports.