Lawmakers questioned child welfare leaders Tuesday over mistakes made by the Department of Children and Families that led to Phoebe Jonchuck's death.

Phoebe Jonchuck was thrown from the approach to the Sunshine Skyway bridge last month. Her father, John, is accused of doing it. There are questions as to whether he is mentally competent to stand trial.

It's come to light that DCF was warned about his mental state twice, but those two calls to the DCF child abuse hotline were brushed aside, an investigation never took place and case workers never removed Phoebe from her father's custody.

On Tuesday, a key House committee grilled DCF Secretary Mike Carroll over the proposed revamp of the hotline and how it should prevent a repeat of the tragedy in St. Petersburg.

"Although I would have taken the call, I could see where there was some confusion with the allegation matrix, the way that it didn't tightly fit into any of the boxes, and so, a less experienced person screened that out," Carroll said. "We have fixed that and that won't happen again."

In Gov. Rick Scott's office, the allegations of negligence by DCF come on the heels of two unfolding scandals at other agencies. That has lawmakers asking hard questions about the administration's competency.

Despite the governor's calls for more money to hire more social workers, the leader of the state Senate is now calling for an independent probe of DCF.

Many lawmakers point out that Phoebe Jonchuck is only the latest child to die after red flags were missed.

"What kinds of analytics do they have at hand to help them in decision support?" Rep. Gayle Harrell, R-Stuart, said. "Have we spent enough money? We spent $30 million."

That's a lot of money for what critics say have been very few results, and now they are demanding answers.

In his testimony, Carroll said DCF can always use more case workers, but the bigger challenge is finding committed workers. The turnover at DCF is among the highest of any state agency.