China Arnold of Dayton is charged with murder, the Dayton Daily News reported.
A judge declared a mistrial at her first trial in 2008 because a 5-year-old boy came forward after the defense rested and said he saw another child put the baby in the microwave. Later that year, Arnold was convicted and sentenced to life in prison without parole when jurors deadlocked on the death penalty.
Her conviction was reversed last year. The appellate court ruled the judge should not have allowed videotaped testimony from a woman who testified at the first trial that Arnold admitted, while they were sharing a cell, that she killed 3-week-old Paris Talley.
Prosecutors were unable to find the witness for the second trial.