Whether the incident is a bank robbery in Stockholm, Sweden, a hijacking of an aircraft over western New York State, a kidnapping in South America, or an attempted prison break in Texas, there are behavioral similarities in hostages, despite geographic and motivational differences. In each situation a relationship develops between people caught in circumstances beyond their control and not of their making and reflects the hostage's use of ego defense mechanisms. This relationship, the 'Stockholm syndrome,' seems to help victims cope with excessive stress, yet is not a blanket affection for the captor. The bond, though strong, does have its limits. In the absence of negative contact with the captor this response is stronger than the impulse to hate the person who has created the dilemma. At an unconscious level, the ego has activated the proper defense mechanisms in the correct sequence--denial, regression, identification, or introjection--to achieve survival. The application for law enforcement involves assuring the safety and survival of the hostage, the crowd, the police, and the captor. To this end, adequate perimeter formation, police training and discipline, and proper equipment are needed. It is suggested, moreover, that the Stockholm syndrome be fostered while negotiating with the captor. This can be done by asking him to allow the hostages to talk on the telephone or to check on the health of a hostage; or by discussing with him the hostages' family responsibilities. The police negotiator must pay a personal price for this induced relationship. Hostages will curse the negotiators, as they did in Stockholm in August of 1973. They will call the police cowards, and actively side with the captor in trying to achieve a solution to their plight, a solution not necessarily in their best interest or in the community's best interest. A hostile hostage is the price that law enforcement must pay for a living hostage. Forty-six references are appended.(Author abstract modified).