Lisa Humphrey has been charged with first-degree reckless homicide in the death of Royality Sanders, found dead April 28 in the Milwaukee home shared by Humphrey, her daughter and two grandchildren, the Milwaukee Journal Sentinel reported Tuesday.
Humphrey told police she had been baby-sitting her grandchildren as well as children from the apartment below her, and fed Royality from a yellow bottle before putting him on a mattress to sleep.
A test of the contents of the bottle found it contained morphine, the Milwaukee County medical examiner's office said, and a blood screen of Royality tested positive for both opiates and oxycodone.
Humphrey first told police she takes pain and sleep medications but hadn't taken any the night she was baby-sitting the infant.
She later admitted to taking medication that night but insisted she did not know how the drugs got into the child's bottle, police said.