Prosecutors say that she put the baby in the microwave after a fight with her boyfriend, whom she told that “the baby would still be alive if you had not cheated on me”. China was said to have been alone when the baby was placed in the oven. It was late at night and her other children were asleep. The baby woke her, she wrapped the infant in a blanket, placed her in a microwave, turned the microwave on and then went outside.
It was Arnold’s third trial in her daughter’s 2005 death. Her first trial ended in a mistrial when new witnesses surfaced just before closing arguments. Her second trial ended in a guilty
verdict and a life sentence. But an appeals court overturned the conviction when it found prosecutorial misconduct and that the trial judge erred in not allowing a relevant witness to testify. ~Source