Investigators said the child, Mason Scott, was found dead after
an Aug. 16 fire at a house in Russellville.
Russellville Police said Christie Scott was taken into custody Monday.
A Franklin County grand jury returned an indictment charging Scott with 3 counts of capital murder.
Authorities decline to discuss the evidence.
Scott was placed in the Franklin County Jail under no bond.
Her first court appearance is scheduled for Oct. 28.
Its unclear if she has retained an attorney.