Standing in a glass booth, a distraught Amanda Jo Stott-Smith heard the charges against her: aggravated murder and attempted aggravated murder.

PORTLAND — A mother accused of murdering her 4-year-old son and trying to kill her 7-year-old daughter by forcing them off a bridge into the Willamette River lost a custody battle over the children with their father a month earlier, according to court documents.

Amanda Jo Stott-Smith and her husband, Jason F. Smith, fought for custody of the children after he left their Tualatin home last year and moved to Eugene, according to court papers.

Police say her 4-year-old son, Eldon Jay Rebhan Smith, and the boy's sister were either tossed 75 feet from a bridge over the Willamette hours before daybreak on Saturday or fell in. They were pulled out of the water during a search. The girl survived and was hospitalized.

Although police have not revealed details of how the two ended up in the water, they are holding Stott-Smith responsible. No possible motive has been given in the case.

A self-described "stay-at-home" mother, Stott-Smith was arraigned Tuesday in Multnomah County Circuit Court.

Standing in a glass booth, a distraught Stott-Smith heard the charges against her: aggravated murder and attempted aggravated murder. In a voice that could hardly be heard in the crowded courtroom, she said, "I understand."

A judge ordered that the 31-year-old remain in custody.

Also on Tuesday, a Washington County court placed the 7-year-old girl — who has not been identified — into the temporary custody of the state. Court records show the mother has a history of domestic violence.

Records also show that she and the children's father were engaged in a custody fight over the children, and she lost.

A judge ruled at the end of April that the children should stay with their father in Eugene, and Stott-Smith could not visit the children at their father's home without his permission.