Dr nemesis and the spy girl

In flagrant violation of the Hippocratic code, the good dr. injects a secret serum (one of his own invention)on a girl he suspects of being a spy. Luckly for him, she
is a spy and confesses so, under the drug's influence.
Suppose the girl wasn't a spy, but was allergic to his
(hardly FDA-tested) serum, and died? What then?

Source: Old comic book