Sonya Spoon (Prince George’s County Police via AP)

A Maryland woman charged with killing her 3-year-old daughter and 1-year-old son has pleaded guilty to two counts of second-degree murder.

Sonya Spoon, 26, entered the plea Wednesday afternoon in Prince George’s County Circuit Court and faces 35 to 45 years in prison, according to the agreement announced by prosecutors.

Spoon’s case stems from the September 2014 suffocation of her children, Ayden Spoon and Kayla Thompson. Police and prosecutors say she covered her children’s heads with plastic bags wrapped with duct tape until they became unconscious. They later died at a hospital.

The killing of Spoon’s children came about a week after she had threatened to kill herself and harm her daughter. Police had escorted her to the hospital for an emergency psychiatric evaluation on Sept. 1 after she made the threats, but she was able to leave the hospital shortly after without medical staff or law enforcement reporting the verbal threats to child welfare officials.

State law requires professionals only to report suspected abuse or neglect, and threats alone aren’t enough to require a report, according to county officials.

In 2015, state lawmakers considered a bill that would require any “health practitioner, police officer or human-service worker, acting in a professional capacity” to report “verbal threats of a substantial risk of imminent harm” against a child to the local department of social services in an effort to close the gap that might have prevented the deaths of Spoon’s children. The house bill, however, was unsuccessful.

Spoon is scheduled to be sentenced in June.