FILE - In this Saturday, Oct. 26, 2002 file photo, a special forces officer carries a woman out of the Dubrovka Theater where hundreds of hostages were held in Moscow, Russia. Russian special forces turned to carfentanil to end a standoff with Chechen separatists using an aerosol version of the opioid, along with the less potent remifentanil, sending it through air vents, according to a paper by British scientists who tested clothing and urine samples from three survivors. The strategy worked, but more than 120 hostages died from the effects of the chemicals. (AP Photo/Gazeta Gazeta, File)