The boys -- ages 7 and 8 -- are charged with murdering an 11-year-old girl

CHICAGO (CNN) -- Two preteen boys charged in the brutal murder of an 11-year-old girl have been ordered to undergo psychological exams to see if they are competent to stand trial.

Juvenile Court Judge Andrew Berman said the tests also will help determine if the boys -- ages 7 and 8 -- were competent enough to understand their rights when they allegedly confessed to the slaying. A psychiatrist's report is due October 2; the boys' next court appearance is set for October 15.

The girl, Ryan Harris, was beaten, suffocated and sexually molested in July. Her body was found August 9, hidden in brush in the South Side neighborhood where the boys live. When questioned, police say the boys confessed.

But in court Friday, defense attorneys contended that details in an autopsy report on Harris showed that a "freak pedophile" was the real killer.

R. Eugene Pincham, an attorney for the 8-year-old boy, said the boys are too small to have caused the severe head injuries found during the autopsy. Other details -- such as the fact that two leaves stuffed in each of Harris' nostrils were meticulously folded four times -- point to a more cunning killer, he said.

"You've got a freak pedophile out there," he said.

Pincham objected to the psychological exam, demanding to go to trial immediately.

"The children will live the rest of their lives with a stigma over their heads that they committed a murder," he said. "The reality is (prosecutors) don't want to prosecute because they don't have a case."

"I believe in our evidence in the case," prosecutor Kip Owen said. "At this point, I believe we have two individuals before the court who participated in this act."

The boys, among the youngest ever charged with murder in the United States, have been released to their families' custody pending trial, and are required to have 24-hour adult supervision.

Reuters contributed to this report.