I Am The Least of Those by Benjamin Vance

Venue is Bangladesh. Two Baptist missionaries travel to Bangladesh and one falls in love with Bengali girl. Conflict with buddy and other missionaries results in main character being enlisted into American Embassy Attaché confidence and employment. Intrigue ensues with character's fiancé being kidnapped and mutilated, both physically and psychologically. During her healing process main character takes his revenge, which leads to armed confrontations and finally redemption.