24. Kristen Gilbert
There have already been a couple stories of dangerous nurses on this list. Kristen Gilbert is another example of a nurse who seemed to be perfectly capable professionally but was actually hiding something more sinister than anyone could imagine.

In total, Kristen Gilbert killed four patients, although she had tried to kill two others in a similar fashion. Her method was what you would expect of a skilled nurse with a dark motive: she induced cardiac arrest in patients by overdosing them on a combination of drugs. She would then try to act as though she were saving them when they coded. She was sentenced to life in prison.
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