A Perry, Missouri woman is charged with murder in an October 2011 drug overdose death.
Christina Schalk, 31, is charged with second-degree murder in the death of 47-year-old Karen Caldwell.
Investigators say that Schalk delivered heroin to Caldwell who later died from an overdose.
Schalk was originally charged with involuntary manslaughter and delivery of a controlled substance. Those charged were amended Tuesday.