KLAMATH FALLS, Ore. (AP) – Authorities say a Klamath Falls man has pleaded guilty to sending cards to former coworkers containing a white powdered pesticide threatened to be anthrax. The U.S. Attorney’s Office for the District of Oregon said 71-year-old Kelly Michael Burns pleaded guilty Monday to eight counts of mailing threatening communications. Court documents say in December 2019, Burns mailed four Christmas cards to former coworkers containing a white powder pesticide identified as carbaryl, a known pesticide toxic to humans, court documents said. The cards were addressed to the victims’ workplace and contained violent threats. Three people at Burns’ former workplace were exposed to the carbaryl, went through a decontamination process, and were given a high-dose antibiotic.