The first time a Miami infant went to the hospital, he had suffered a broken leg his mother said was the result of a fall from a chair. Child protection workers did not act.

Investigators never knew about the infant’s second injury, a cracked rib.

The boy’s third injury nearly killed him.

On Thursday, a Miami-Dade child welfare judge blasted the Florida Department of Children & Families for failing to take any action to protect the boy until it was too late. The child was removed from his mother’s custody earlier this month after he suffered the life-threatening laceration of his liver. Judge Rosa C. Figarola said in court the child’s liver had been “severed.”

“You’re lucky you’re not at a funeral right now,” Figarola fumed at a hearing over the fate of the boy, whose first birthday was Monday.

Thursday’s hearing took place as DCF administrators were already under enormous scrutiny.

Beginning in May, four small children who previously had been the subject of DCF investigations died within a six-week period. The deaths — all but one in Miami-Dade and Broward counties — occurred just as the department was set to unveil a child protection “transformation” that DCF Secretary David Wilkins insists will dramatically improve the agency’s record at keeping children safe.

On Thursday, Wilkins announced that his chief of staff, Amanda Prater, had left the agency. Jane Johnson, the department’s child abuse prevention coordinator and a former director of the state’s Agency for Persons with Disabilities, will replace Prater.

Not at fault

Johnson entered the fray Thursday by insisting to reporters that DCF was not the culprit in the recent tragedies.

“When a child dies,” Johnson told The Florida Times-Union, “it’s not because DCF dropped the ball. It’s because their families failed to protect them.”

Figarola, who pronounced herself “very disturbed” by the latest case, said the injured infant is further evidence of system-wide failures at the long-troubled agency.

“The allegations that there are systemic issues at play here, honestly, are being substantiated,” the judge said. “The checks and balances are not working. We’re lucky we don’t have another death in our county.”

Both the infant and his 4-year-old sister — who are not being named by the Miami Herald to protect their privacy — were sheltered by DCF last week after the infant was hospitalized.

The most recent incident is being investigated by the Miami Gardens Police Department.

About two weeks ago, the department received a call from Jackson North Medical Center that the youngster had suffered a lacerated liver, as well as a “healed” rib fracture, said Police Detective Elio Tamayo.

The baby was transferred to Ryder Trauma Center. No charges have been filed.

The little boy first came to DCF’s attention three months ago, Figarola said, when he was hospitalized with a broken femur, or thigh bone. The boy’s mother told a DCF investigator that she had been sitting with him in a chair, got up, and left him there. She suggested he broke the bone when he fell off the chair.

When the infant’s case first appeared in Miami’s child welfare court, Circuit Judge Cindy Lederman, a nearly 20-year veteran of the children’s bench, immediately asked DCF administrators to review the case.