At least six city employees will be fired for improperly handling concerns about a woman's care for her four daughters, who were later found dead in their home, Mayor Adrian M. Fenty said Monday.

The decomposing bodies of the girls — ages 5 to 17 — were found Wednesday when deputy U.S. marshals served an eviction notice at the apartment. Their mother has been charged with murder.

A social worker at the school where the oldest girl was a student, Kathy Lopes, tried twice in April to raise concerns about the family.

Click here for more from MyFoxDC.com.

At a news conference Monday, Fenty played tapes of two calls Lopes made after the girl, Brittany Jacks, stopped going to school. The social worker describes visiting the house, but not being let in by the mother, Banita Jacks.

Lopes said Jacks told her she did not want Brittany going to school because she was afraid the girl would run away. Lopes reported seeing two or three younger children who also were not in school.

In a follow-up call, she expresses frustration at being transferred among several departments.

"It appears the mother is suffering from some mental illness and is holding all the children hostage," Lopes says on the tape.

Jacks told investigators the children were possessed by demons and died in their sleep.

It was not clear who the six employees were who are being terminated.

Fenty praised Lopes, who works at the Booker T. Washington Public Charter School.

"Unfortunately, she stands out really because so many other people didn't do their job in the way they're supposed to," Fenty said. "The sense of urgency that she showed should be shown in every case and every call that comes through our hot line."

Lopes' call was not the first time someone had tried to alert city officials about the family's situation.

In July 2006, a nurse who had been treating the father of Jacks' youngest two daughters contacted the Child and Family Services hot line to report the family was living in a van and that both parents were struggling with substance abuse, officials said. The nurse couldn't provide an address for the family so social workers did not follow up.

Authorities have said the girls died at least 15 days before they were found. Jacks' statement to police indicated they had been dead for months. The medical examiner's office has said there is evidence that Brittany was stabbed and that Tatianna Jacks, 11; N'Kiah Fogle, 6; and Aja Fogle, 5, had other signs of trauma.