KANSAS CITY, Mo. -- Attorneys gave opening statements Monday in the trial of the man accused of killing and decapitating a girl more than seven years ago.

Harrell Johnson's attorney, Kenton Hall, said Erica Green's death was unintentional. Hall admitted that Harrell Johnson kicked the girl, but said it was not the premeditated act necessary for first-degree murder.

Jackson County special prosecutor Tim Dollar said Harrell Johnson, who was dating Green's mother at the time, killed the 3-year-old girl by kicking her in the head and then denying her medical treatment for hours or possibly days. Dollar said Johnson and the child's mother took her lifeless body behind a church, where he cut her head off with a pair of hedge trimmers.

For years after the girl's body and head were found, the child's identity was unknown. After four years of searching, a tip from Harrell Johnson's grandfather confirmed that the girl known only as "Precious Doe" was Erica Green.

Erica's mother, Michelle Johnson, who married Harrell Johnson a year after Erica Green's death, pleaded guilty to participating in the crime. She was sentenced to 25 years in prison. Johnson is expected to testify against her husband in the trial as part of her plea agreement.

A Kansas City police officer who found the girl's body and two crime scene technicians also testified Monday.

The trial is expected to last about a week. If convicted of first-degree murder, the only possible sentence for Harrell Johnson would be life in prison without parole. Prosecutors are not seeking the death penalty, partly because Johnson agreed to withdraw his request to have the case moved out of Kansas City.