The baby was hers, Kimberly Sankey finally admitted.
Detectives said Wednesday the 16-year-old told them she made up the story about finding the newborn girl in a lawn chair on the porch of her family's home near Haines City on Oct. 22.
Sankey was scared and embarrassed and kept her secret for nearly four days before finally telling investigators Friday what really happened.
She said she didn't know she was pregnant until she gave birth while taking a shower late on Oct. 21, sheriff's Maj. Marvin Pittman said.
The next morning, she and her mother called 911 and reported the baby had been left on their porch, at 6211 Old Polk City Road.
Investigators believe Aretha Sankey, Kimberly's mother, knew nothing about her daughter's pregnancy and the birth until her daughter told her on Friday, moments after she admitted it to detectives.
"I took Kimberly and had her tell her mother," Detective Alan Cloud said. "It wasn't fun. But she was supportive of her daughter."
Detectives didn't file criminal charges stemming from the baby's death. The baby was born two to three months prematurely and an autopsy found it unlikely she would have survived even with medical care.
"There was no evidence that this was a criminal act _ i.e., that she had the baby and killed it, or that she was neglectful," Pittman said.
Detectives haven't ruled out charging her with filing a false report.
The final decision on criminal charges in the baby's death will be up to prosecutors in State Attorney Jerry Hill's office.
"Typically, when the medical examiner finds that premature birth was the cause of death, there are no charges pending," said Russ Knowles, executive director of the State Attorney's Office. "However, we can't comment on this case or any specific case."
The Sheriff's Office chose to delay publicizing its findings in the case until Wednesday to ensure that detectives had time to complete their reports and to confer with the medical examiner and the state attorney's office, Pittman said.
Sheriff's detectives closed their investigation Wednesday and forwarded it to the state attorney's office for review, which they said was routine in such cases.
Sankey first told detectives she found the baby wrapped in a blanket early in the morning when she went outside to get a lipstick from her car as she got ready to go to school early last Wednesday morning. She said she found the baby wrapped in a pink blanket on a plastic lawn chair.
The baby girl, with its umbilical cord still attached, was less than 24 hours old when Sankey and her mother called 911. The 10th-grader then went to her classes at Haines City High School.
Detectives at first believed her story.
"We received some tips Thursday morning there was another girl in the neighborhood who might be the mother and we focused on that the rest of the afternoon," Cloud said. "When that didn't pan out we talked about it and decided to look at (Kimberly) more closely."
After Kimberly admitted she was the mother of the baby, detectives encouraged her to undergo a medical exam to ensure that she had survived the trauma of childbirth without injury, Cloud said. The exam confirmed that she recently had given birth, Cloud said.
Aretha Sankey and Kimberly Sankey could not be reached for comment. Pittman said he believed they were trying to avoid the news media.
"I told the mother today (Wednesday) we were going to have to release this information and she was extremely upset about it," Pittman said.
"It's a tragic story the whole way around," Cloud said. "There's no winners."