STOCKTON, Calif. – Tearful and trembling, a Sunday school teacher apologized in court Monday for kidnapping and murdering her young daughter’s playmate but didn’t address the main question surrounding the shocking crime that will keep her in prison for the rest of her life.

“I still cannot understand why I did what I did. This is a question I will struggle with for the rest of my life,” Melissa Huckaby said before a judge sentenced her to life in prison without the possibility of parole.

The only comfort that Huckaby offered the family of 8-year-old Sandra Cantu was that she “did not suffer, and I did not sexually molest your daughter.”

Authorities disclosed an investigative summary that depicted a brutal killing that left the child with wounds to her head and body, including injuries to the outside of her genitals that were consistent with a bloodstained rolling pin found inside a church where Huckaby had taught. The stain matched Sandra’s blood, prosecutors said.

A pathologist’s report listed the official cause of death as “homicidal asphyxiation.” Prosecutors believe Huckaby drugged the girl then smothered her with a cloth soaked in rubbing alcohol.

Sandra’s body – found in a black suitcase pulled from an irrigation pond – contained alprazolam, a prescription sedative commonly used to treat anxiety. Prescription bottles of the drug were found in Huckaby’s purse and home, prosecutors said.

Huckaby, 29, pleaded guilty last month to first-degree murder with a special circumstance of kidnapping. As part of a plea deal, prosecutors took the death penalty off the table and dropped all other charges, including allegations that she sexually abused the girl.

During sentencing, Huckaby addressed the victim’s mother, Maria Chavez.

“I’m asking you, Maria, for your forgiveness,” Huckaby said. “I can’t imagine forgiving someone who harmed my daughter.”