An attorney has been hired to represent a Tennessee woman charged with fatally stabbing four of her children but declined to discuss the case.

Craig Morton says he is representing 29-year-old Shanynthia Gardner, who has been charged with first-degree murder in the deaths of her three daughters and one son, all younger than 5.

A judge waived Gardner's arraignment during a Tuesday hearing at which she appeared by video. Outside court, Morton declined to talk about the case.

Shelby County sheriff's officials say Gardner stabbed her children Friday afternoon at her apartment. Court documents say she acknowledged killing them in a phone conversation to their father.

A fifth child, age 7, escaped the attack.

Authorities have not said why they think she killed her children. Investigators are looking into whether she has mental health problems.