Baltimore police say a mixture of methadone and baby formula killed a 5-month-old girl and led to first-degree murder charges against the child's mother: Teresa Ann Younger, 25, of the 4600 block of Freedom Way in Northeast Baltimore.
The infant, Matia Grant, died the morning of March 4 at Bon Secours Hospital.
The baby was not breathing when Younger took her to the hospital for treatment.
Younger, arrested Friday, is accused of lacing the baby's formula with methadone the night of March 3 because the child was restless, homicide detectives said.
Younger is being held at the Baltimore City Detention Center. Bail was denied.
An autopsy on Matia revealed high levels of methadone in the child's blood and liver.
In large doses, methadone -- an addictive syrup given to addicts as a less-dangerous substitute for heroin -- can cause the respiratory system to fail.