An Ohio mother confessed Tuesday to killing her three sons because their father was paying more attention to them than the couple’s 3-year-old daughter.

Logan County, Ohio, prosecutor William Goslee said Brittany Pilkington, 23, confessed that she killed each of her three sons in a span of 13 months, with the most recent child's death taking place Tuesday.

Authorities were called to Pilkington’s residence just after 3 a.m. Tuesday after a 911 call from Pilkington reporting her 3-month-old son Noah was not breathing. He was pronounced dead at the hospital.

Noah and his 3-year-old sister, Hailey, had been in foster care until about a week ago, Goslee told the Springfield News-Sun. During a recent hearing, both the prosecutor's office and the Logan Family Department of Job and Family Services remained adamant that the children shouldn't be returned to their parents, Goslee said, because investigators did not yet know the cause of death of two other Pilkington children.

On July 22, 2014, 3-month-old Niall Pilkington was found dead by his father, Joseph Pilkington, when he returned home from work. The cause of death was listed as undetermined at the time, based on testing and lack of evidence, according to police.

On April 6 of this year, 4-year-old Gavin Pilkington was found dead by his father – again when he arrived home from work. The open investigation into Gavin’s death by the coroner’s office and police department is continuing, the chief said.

Brittany Pilkington told investigators Tuesday that she used a blanket to kill the children. The boys’ sister has been removed to foster care again.

Ed Cummins said he last saw his daughter Brittany at a funeral for one of her sons.

“I’m blown away,” Cummins said. “I have no clue what to think. She was quiet, wasn’t broken down, but I thought maybe she was like me, holding tough for the family.”