O’FALLON, Ill. (AP) — Authorities say a southern Illinois woman is facing charges she planned to asphyxiate her three young children with carbon dioxide.

The St. Clair County State’s Attorney’s office says 29-year-old Emily Sparks of O’Fallon, is being held in the St. Clair County Jail on three counts of attempted murder. O’Fallon police Lt. Nicholas Schmidt says her two sons and daughter, ages 3, 5 and 7, are being cared for by relatives.

Schmidt says police received a tip that Sparks had planned to kill her children Dec. 4 and learned that Sparks had purchased a canister of carbon dioxide. She changed her mind at the last minute.