By Kirsten McIntyre, NEWS 9

OKLAHOMA CITY -- An Oklahoma City father said he's repeatedly warned authorities about his ex-wife's mental state, and now she's under investigation for allegedly killing three babies in three years.

Joseph Young said he's been fighting the system for months, but was able to accomplish very little in his pursuit.

His ex-wife, Sweetcherry Ann Haliburton, was jailed in Missouri and charged with killing her six-week-old baby.

Young and his sister was frustrated after no one responded to their pleas for help.

"I've been at DHS meetings where DHS workers have mockingly laughed at him," Young's sister Elizabeth Ponce said.

Young warned them Haliburton was a killer. When her marriage to Young ended in 2002, Haliburton was eight-months pregnant, carrying Young's baby.

When a little girl was born, Ft. Worth authorities placed Haliburton in state custody.

"I was never told why," Young said. "I was told that was personal."

Young was later awarded sole custody of the child. Four years passed before Haliburton contacted Young, claiming she received help.

"At the time, I was struggling with my daughter about her emotions toward her mother," Young said.

Wanting to help ease his daughter's sadness, Young said he and Haliburton had reconciled, but the relationship once again did not last.

Young later discovered Haliburton gave birth to a boy named Eiam.

The child died shortly after Young received the news.

"The medical examiner crimes against children, they all told me it was SIDS," Young said.

Young said he felt sorry for his ex-wife, especially when he discovered she'd previously had a baby from another relationship a year earlier that also died of SIDS.

"It made me very concerned for her," Young said. "I didn't want the mother of my daughter to commit suicide."

The two reconciled again, but shortly after Young became suspicious that Haliburton had killed the two babies.

Following a dispute, Young was arrested and consequently lost custody of his daughter. Meanwhile, a pregnant Haliburton left Oklahoma.

On September 25, she drove to a Missouri hospital with a baby boy dead in her car.

Young said he believes the child is also his.

"The system is broken," Young said. "It deals with men in a slanted way."

The domestic abuse charge against Young was dropped, and he hopes to have custody of his daughter back in a few weeks.

Texas authorities had been in contact with him about taking custody of the baby boy, but they didn't have possession of the child before he was smothered last week.

Authorities have since reopened the cases of the two prior child deaths.