Ana, 13, was sleeping in bed when her father struck her three times on the back of her head. Younger brother Anthony, 12, tried to run away.

But his father, a laborer and former boxer, dragged him back into the bedroom and killed him. Pérez, 48, tried to hang himself from the ceiling fan, but it collapsed under his 110-pound weight.

"You will never be happy, " he wrote Maria Christina González, the children's mother, in a suicide note.

It was Oct. 13, 2000.

Ana and Anthony are among at least 100 Florida children who died while under the state's protective supervision - after questionable investigations by the Department of Children & Families failed to appreciate the gravity of key warning signs that families were in trouble, The Herald has found.

Before Ana and Anthony died, several calls warned the DCF hot line that the children were in danger. But the probe soured: Hot-line operators mistakenly concluded the mother was putting her children at risk.

And the lead investigator missed critical opportunities to find González and her children - because he had not checked court files that would have told him where the children attended school and the mother worked.

"I was juggling so many cases, " said Derrick Heath, now a DCF supervisor. "I tried three times to find the family but they were never home. Things happened too quickly. It's not easy when two children are dead."

The first two warning calls came Oct. 7, six days before the deaths.

"There is concern that her children may be in danger, " the report notes. "Father has a history of domestic violence against the mother. Father has a history of drug use and drinking and had been imprisoned for domestic violence against the mother."

Two more warning calls to the DCF followed the next morning.

Somehow, hot-line operators wrongly believed González was the culprit by not protecting the children from the threats. The DCF ordered a visual inspection of the family: "If allegations of failure to protect are true and child is at risk remove and file petition."

WRONG JUDGMENT

"The hot line incorrectly passed judgment on the mother, " said Nancy Barshter, a member of a state-wide death-review team that examined the DCF's handling of the case. "I don't think DCF totally put together the danger to her and her family."

On Oct. 8, the caseworker went to the house at 1 p.m. but found no one at home.

Heath filled out a Child Safety Assessment that same day, noting that the DCF had three prior cases with the family, including a 1995 incident where Pérez nearly beat González to death.

The assessment helps caseworkers and supervisors determine how much danger a child faces - on the basis of the child's age, the family's history, caregivers' criminal records and other factors. Among the questions asked:

* Does parent or caregiver have a history of domestic violence as a victim or perpetrator?

Heath checked off "Suspected." "The [adult parent] in this case is very violent." * Does parent, caregiver have a criminal history?

"Not known."

Public records showed Pérez had been released from state prison in March 1999 after completing part of a five-year sentence for trying to kill González.

* Is there is a pattern of continuing, escalating and/or increasing frequency of incidents, regardless of findings?

"Not known."

But much was known by others. On Oct. 2, González had filed a restraining order against Pérez and reported his threats to police. The restraining order contained the name of Pérez's employer, González's employer and the childrens' schools. Portions of the DCF's own hot-line report indicated that Pérez was "stalking" González and banging her car with chains. The hot-line caller also knew the family's whereabouts.