8. Kristen Gilbert
Imagine poisoning your victim, and then responding to the distress call yourself! Yep, that’s exactly the strategy that Kristen Gilbert used as a nurse to murder 4 of her patients and attempt the same on 2 more.
She executed her sinister tricks at the Veteran Affairs Medical Center in Massachusetts. Her choice of weapon? Epinephrine, an untraceable heart stimulant that caused cardiac arrest. She was finally convicted in 1998 and is currently serving her life sentence in Forth Worth, Texas.