Complex sentence: Henke was interned in the interrogation center known as P. O. Box 1142 in Fort Hunt, Virginia, where his interrogators threatened to hold him to his agreement to cooperate or be extradited to England to face war crime charges.
Split into simpler sentences: Henke was interned in the interrogation center known as P. O. Box 1142 in Fort Hunt, Virginia. While there his interrogators threatened to hold him to his agreement to cooperate or be extradited to England to face war crime charges.