The next time you complain about your doctor, thank your lucky stars that at least you’re not a patient of Virginia Helena Soares de Souza, a 56-year-old physician in Curitiba, Brazil who is accused of killing at least seven terminally ill people in order to free up beds in her hospital. Even scarier is the fact that she convinced seven (SEVEN!) other medical professionals — three doctors, three nurses and a physiotherapist — in the Evangelical Hospital to help her carry out the fiendish plot.

The group allegedly killed the victims using a two-pronged approach: first, using a “drug cocktail” of painkillers, sedatives and anesthetics to increase the patients’ reliance on respirators, and then by restricting the oxygen levels in those ventilation devices, causing them to die from asphyxiation. De Souza was the head of the intensive care unit (ICU) at the hospital and was quoted in recorded telephone conversations as stating that the crowded conditions in the ICU were making her “itch” and that she wanted to clean up the “clutter.”

She and her seven cohorts are charged with murder and are awaiting trial. Investigators believe the total number of victims could rise much higher and are combing through the 1,700 deaths that occurred at the hospital between 2006 and 2013, the years of de Souza’s deadly activity. Around 300 of those patients were under her care. De Souza has pleaded not guilty.

Throughout history, some of the most prolific serial killers have been medical professionals who have easy access to helpless victims. These so-called “angels of death” include:

• Nurse Jane Toppan confessed in 1901 to killing 31 patients, acquaintances and even relatives throughout Massachusetts from the 1880s through the turn of the century.
• Former hospital orderly Donald Harvey claims to have killed 87 patients in Kentucky and Ohio during his 17-year career through the ’70s and ’80s, although authorities estimate the number more in the 37 to 57 range.
• Austrian nurse’s aides Waltraud Wagner, Stephanija Mayer, Maria Gruber and Irene Leidolf admitted to killing up to 42 patients in the geriatric ward in Lainz General Hospital in Vienna, where they worked between 1983 and 1989.
• Efren Saldivar initially confessed to killing 50 people while working as a respiratory therapist in the Los Angeles area between 1988 and 1998, but eventually he pled guilty to “only” six deaths.
• In 1999, nurse Orville Lynn Majors was convicted of killing six patients under his care in the ICU at Vermillion County Hospital in Clinton, Indiana, although it’s believed the number of victims could be as high as 130 — all in just a two-year span between 1993 and 1995.
• English doctor Harold Shipman was found guilty in 2000 of the murders of 15 of his patients, but investigators believed he killed anywhere between 250 and 450 over a two-decade reign of terror.
• Dr. Michael Swango was convicted in 2000 of the poisoning deaths of three patients, but he is suspected in as many as 60 deaths in multiple states and even in Zimbabwe throughout the ’80s and ’90s.
• Although nurse Charles Cullen admitted to killing around 40 patients in the 10 New Jersey and Pennsylvania hospitals in which he worked between 1988 and 2003, there is reason to believe he had a hand in as many as 400 deaths.
• In 2006, German nurse Stephan Letter was convicted of the murders of 29 elderly patients at a clinic in Bavaria.

(Sources: Sky News, CNN)