WARNING: Some readers may find details disturbing

Two young sisters had numerous broken bones when they were discovered by a babysitter inside furniture boxes left in a dark, barricaded, basement room at a northeast Edmonton townhouse, CBC sources say.

CBC News has spoken to a number of sources to piece together new details that led to charges of attempted murder, unlawful confinement and abandonment against two Edmonton mothers in December.

Days after the charges were laid, Edmonton police Chief Rod Knecht told CBC News he was aware of the details surrounding the case.

"I think it's one to pay attention to," Knecht said. "I do have the details. And it's very disturbing."

A court-ordered publication ban protects the names of the children, so their mothers' names cannot be released. CBC News is identifying the mothers by their initials: JL, age 24, and AM, 23.

JL has two young daughters, ages 6 and 3. AM has three children: ages 2, 3 and 5.

They all lived in a two-storey townhouse in northeast Edmonton.

The sources gave CBC this account.

On Dec. 16, the two mothers decided they wanted a night out. Their regular babysitter was not available, so they called in someone new.

The mothers told the babysitter that three children were upstairs and two others were downstairs. The babysitter was told not to worry about the downstairs children and to focus on the three young ones upstairs.

After the mothers left, the babysitter checked on the children who were upstairs. She thought they looked malnourished and became alarmed.

At that point, she decided it was important to check on the children downstairs.

But a piece of furniture was blocking the downstairs door. The babysitter pushed it out of the way and entered a dark room.

Shocking discovery

Inside the room were two closed furniture boxes. A three-year-old girl was inside one of the boxes. Her six-year-old sister was inside the other box.

The six-year-old was unconscious. The babysitter called 911.

Both girls were transported by ambulance to hospital. The older girl spent days in intensive care fighting for her life.

The sources told CBC News that the two children had numerous broken bones. Subsequent testing revealed the three-year-old had likely been eating her own hair. It was found in her stomach.

'Psychologically they would die'

The girls have since been released from hospital and are now in foster care. People close to the case suggest the physical and psychological scars will be long lasting.

Edmonton psychologist Les Block is not treating the two girls, but has counselled many victims of childhood abuse. CBC shared the details of the case with him.

"I have to get over the shock of what actually occurred," Block said. "The shock of these children being placed in such horrific circumstances has to be put to the side in order to try to make sense of what's going to be happening to them now and into the future."

He said the children could face a lifetime of difficulty as they try to trust, adapt and make sense of what happened to them.

He speculated on the psychological impacts of being left inside a box in a dark barricaded room.

"You would die in that moment," said Block. "Psychologically they would die. Now they have to be brought back to life. They have to be resuscitated, and assisted and nurtured, and brought back to life. Because that part is a death."

Charges laid

The two women have been charged with the attempted murder of the older girl and the aggravated assault of her three-year-old sister.

Both women also face the following charges related to both girls:

Abandonment

Unlawful confinement

Criminal negligence by not providing medical attention

Failure to provide the necessaries of life

AM is also accused of assaulting two of her children with a belt.

The three children who were upstairs in the home have also become wards of the province. According to court records, they were allegedly unlawfully confined by the two women between July 1 and Dec. 16.

'Leave no stone unturned'

Knecht told CBC News he received notice of the case the same night the children were discovered. After hearing the details, he said, "I'm personally involved and personally interested in this and personally watching it.

Police chief Rod Knecht instructed his investigators to make this case a 'top priority.' (CBC News )

"My instructions were to leave no stone unturned," said Knecht. "So I think we even assigned more resources to it as a consequence of that discussion. So this is top priority by everybody.

"We want the public to know [about the case.]"

But on Thursday afternoon, an EPS spokesperson declined to provide any further details because the matter is still under investigation.

AM and JL are scheduled to make their next court appearance on Monday. They remain in custody at the Edmonton Remand Centre.