In her letter of resignation, the longtime director of the Indiana Department of Child Services lashed out at the governor's office, warning that a continuation of its policies will "all but ensure children will die," IndyStar has learned.

Mary Beth Bonaventura, who has worked in child welfare for 36 years, said she could no longer in good conscience stand by and watch Hoosier children "being systematically placed at risk, without the ability to help them."

"I feel I am unable to protect children because of the position taken by your staff to cut funding and services to children in the midst of the opioid crisis," she wrote in the Dec. 12 letter to Gov. Eric Holcomb. "I choose to resign, rather than be complicit in decreasing the safety, permanency and well-being of children who have nowhere else to turn."

More:Indiana Democrats demand investigation into outgoing DCS director's claims

Without serious changes, Bonaventura warned, "I fear lives will be lost and families ruined."

On Monday, Holcomb told IndyStar he believes the state is taking "appropriate steps," including increasing DCS' budget by $450 million. He said he respects and appreciates Bonaventura's commitment to children.

"I wish her well," he said, "and I'll continue to focus on how to meet the needs of Hoosier families and children."

Former Gov. Mike Pence appointed Bonaventura to the helm of the child welfare agency in 2013. Prior to that, she spent 31 years working in the Lake County juvenile court system as a referee, magistrate, then judge. Former Gov. Evan Bayh appointed Bonaventura as Lake Juvenile Court judge in 1993, and voters retained her by large margins until her move to DCS.

Bonaventura's letter to Holcomb, which was obtained by IndyStar, outlines four reasons she believes the state is threatening the lives of children.

First, Bonaventura said Holcomb's office stripped her of power to run the agency she is responsible for.

She said the governor's office placed Eric Miller as her DCS chief of staff — someone with no child welfare experience — because he "was an asset during the campaign." Miller, who could not be reached by IndyStar for comment, has moved among various state agencies since December 2007, according to his LinkedIN profile. He was chief of staff for the State Department of Health prior to joining DCS.

Using the position and authority given by Holcomb's office, Bonaventura argued, Miller has engineered his own hires, bullied subordinates, created a hostile work environment, exposed the agency to lawsuits, overridden her decisions, been 'brazenly insubordinate" and made cost-cutting decisions without her knowledge. She said her attempts to "rein him in" haven't been supported.

Bonaventura argued DCS has not been able to spend all of the funding it has been allocated. The director said she has repeatedly tried to secure additional funding, but Miller is "bent on slashing our budget in ways that all but ensure children will die."

When reached Sunday, Bonaventura declined comment on her letter. She referred IndyStar to the governor's office.

"Eric Miller has significant experience and was a highly successful chief of staff at the Indiana State Department of Health for Dr. Jerome Adams — and his expertise has been put to use to help DCS administer services more effectively," Holcomb's Press Secretary, Stephanie Wilson, said Monday in a statement.

She did not directly respond to the concerns raised in Bonaventura's letter.

Second, Bonaventura wrote that the state is jeopardizing the relationship she's built with child welfare providers and the work DCS has been trying to do to update its rates and licensing.

"Foster parents, child-placing agencies and residential treatment facilities are the backbone of the child welfare system," she wrote, "caring for our most traumatized and vulnerable children on a daily basis. Efforts are now being made to undermine the collaborative relationship that has been established and return to the adversarial, litigious relationship that predated me."

Third, Bonaventura said DCS' Child Support Bureau is "on the verge of collapse due to antiquated technology" — a collapse that would affect prosecutors and every parent who receives or pays child support.

She said Holcomb's staff abruptly ordered her to cancel the plan for a new system despite years of work to secure federal approval and matching funds. Bonaventura accused the governor's administration of risking "a financial crisis for millions of Hoosier families."

Finally, she warned that efforts by Holcomb's office to reduce or cap staffing levels of family case managers and child welfare attorneys "will lead to disastrous results."

She said the plan to reduce contract amounts with providers by nearly $15 million will leave more than 1,000 families without appropriate court-ordered services. She said Holcomb's office allowed DCS to request only a fraction of the funding and staffing needed to protect kids.

Wilson said the governor's office continues to review the best ways to provide services for children.

"Across all state agencies, it’s our job to find the most efficient and effective ways to provide government service," WIlson said. "If you pay too much for services, you can’t provide as many of them to those in need."

Bonaventura, whose resignation will be effective Dec. 27, warned that anyone hired to replace her will be unsuccessful unless the problems outlined in her letter are resolved.

Indiana Democrats on Monday called for an investigation into Bonaventura's claims.

Holcomb said his office has begun its search for a new director.

"I'm looking for someone who will share the same commitment for the health and well-being of our children," he told IndyStar, "and someone who will work collaboratively with other agencies that share that mission."

IndyStar columnist Matthew Tully contributed to this report.

Call IndyStar reporter Marisa Kwiatkowski at (317) 444-6135. Follow her on Twitter: @IndyMarisaK.