A Long Beach woman whose 11-month-old daughter died of a methadone overdose pleaded guilty to one felony count of willful cruelty to a child and was sentenced to 12 yeas in prison Monday, according to the Los Angeles County District Attorney’s office.

Charissa Ranee Bailey, 31, was a drug addict at the time of her daughter death, according to prosecutors.

On April 24, 2013, a methadone clinic gave Bailey a week’s supply of the drug and warned her to keep it locked in a container where a child couldn’t get it, the district attorney’s office said in a statement.

Bailey’s daughter was found dead the next day, according to prosecutors. Authorities later determined she died from ingesting methadone.

“According to testimony given at the preliminary hearing, the defendant gave the child methadone to soothe the child,” prosecutors said in the statement.

Police arrested Bailey in March 2014, after investigating the girl’s death for almost a year.

Authorities originally charged her with murder.