An Ohio woman accused of killing her three sons over a 13-month period out of jealousy at the attention her husband paid them has been indicted on aggravated murder charges and could face the death penalty.

Aggravated murder charges against Brittany Pilkington in Bellefontaine (behl-FOWN'-tihn) were announced Tuesday by the Logan County prosecutor.

Investigators say the 23-year-old smothered two sons, one in July 2014 and the other on April 6. Authorities took custody of her third son after he was born three months ago, but a judge allowed him to return home because there wasn't conclusive evidence the older boys had been killed. The third son died Aug. 18.

Pilkington's mother said Pilkington told her in a jailhouse phone call that she's innocent.

Pilkington is jailed on $1 million bond.