A 10-year-old boy, who is described by his mother as having mental difficulties, is alone in a Pennsylvania county prison cell, charged as an adult with killing a 90-year-old woman. Prosecutors say they had no choice but to charge him in criminal court and house him in an adult correctional facility; the law requires it.

In Pennsylvania, homicide charges must be filed in adult court.

"It's ridiculous. ...The idea of prescribing criminal responsibility to a 10-year-old defies all logic," Marsha Levick, deputy director and chief counsel of the Juvenile Law Center, a public interest law firm, told 48 Hours' Crimesider.

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"The Supreme Court has recognized that teens and adolescents hold lesser culpability. Their brains are obviously still developing and they're developmentally immature. Multiply that for a 10-year-old."

[Editor's Note: CBS News is not naming the boy involved in this case due to his age. Instead, we will refer to him as T.K. for the purpose of this article.]

T.K. was arrested October 11 and charged with criminal homicide in the beating death of Helen Novak, a 90-year-old woman being cared for by the boy's grandfather.

"I killed that lady," T.K. told investigators, according to a police affidavit.

The affidavit alleges T.K. told police he became angered when Novak yelled at him, so he grabbed a cane, put it around her throat and punched her repeatedly.

"I was only trying to hurt her," the affidavit quotes the boy as saying.

The boy's attorney, Bernard Brown, says his client doesn't seem to understand the gravity of the situation.

Brown told CBS affiliate WYOU that when he visited the boy at the Wayne County Correctional Facility last week, the boy compared his prison jumpsuit to "a Halloween costume he would probably never wear."

Brown declined to request bail for the 10-year-old last week, saying his family isn't ready to have him released into their custody.

Brown said the boy's family believes he is being treated well at the county prison, where he is being housed alone in a cell and kept away from the general population. He said the boy was being provided coloring books.

But Levick, of the Juvenile Law Center, says the last place T.K. belongs is in a county jail.

"He's effectively in isolation. He's being denied the opportunity for regular interaction, denied education, denied the opportunity for reasonable activity. That, in of itself, will be harmful to him," Levick says.

The boy would be much better suited to the juvenile justice system, where he would likely receive therapy and counseling services, she says, and where the primary goal is rehabilitation, not imprisonment.

According to statistics from the Juvenile Law Center, studies have found that youth imprisoned in adult facilities are more likely to suffer physical and emotional abuse and to recidivate -- that is, become repeat offenders.

The organization says studies show that youth in adult prisons are twice as likely to report being beaten by staff, and nearly 50% more likely to be attacked with a weapon than children placed in youth facilities.

Juveniles in confinement are much more likely to be sexually abused than incarcerated adults, and are 36 times more likely to commit suicide in an adult facility than in a juvenile facility, according to the organization.

Besides Pennsylvania, only one other state - Florida - has a statutory exclusion that requires all homicide charges to be filed in adult court.

But Melissa Sickmund, director of the National Center for Juvenile Justice, told Crimesider that while it "seems severe" when a very young child is charged as an adult with murder, it's "a rare event," simply because a very small percentage of youth are accused of killing.

Instead, she says it's more concerning to look at data from a state like New York, where anyone 16 and older is considered an adult and any crime they are charged with automatically goes to criminal court.

"They're not even mature enough to make a decision about whether they smoke or drink and yet we're going to hold them as criminally responsible as a 45- or 50-year-old?," Sickmund says.

Sickmund also says that Florida is another state that has problematic juvenile justice laws. A report issued by the Human Rights Watch earlier this year criticized the state for "arbitrarily and unfairly" prosecuting children as adults under its Direct File statue, which affords prosecutors the decision of whether to begin prosecution in juvenile or criminal court.

Brown, T.K.'s attorney, said he plans to seek to have the case transferred to juvenile court. A spokesperson for the Pennsylvania Attorney General's Office says they have not decided whether they will contest the move. A mental health evaluation for the boy is pending and his next court date is scheduled for Wednesday.