Brazilian doctor Virginia Soares de Souza has been charged with killing seven patients in order to free up beds at a hospital intensive care unit, according to a Health Ministry investigator. The Brazilian investigator also said Wednesday that De Souza may be responsible for as many as 300 deaths. Prosecutors say that the 56-year-old De Souza and her medical team administered muscle-relaxing drugs to patients, then lowered their oxygen supplies, causing them to die of asphyxiation. Prosecutors also said that wiretaps of De Souza's phone conversations revealed her motives: "I want to clear the intensive care unit. It's making me itch," she said in one recording. "Unfortunately, our mission is to be go-betweens on the springboard to the next life."