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An 11-year-old girl who was allegedly raped by her brother gave birth at home, and now he and their parents are facing criminal charges.

The girl gave birth to a boy in a bathtub in St. Charles, Missouri, according to a probable cause statement.

Her biological brother, who is 17, was charged last week with incest, statutory rape and statutory sodomy of a person younger than 12, while her parents were charged with child endangerment. Police say the girl's parents did not provide medical care to their daughter after she gave birth.

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NBC News is not naming the girl's parents or brother because it would identify the victim.

Police started investigating on Feb. 11 after the girl's parents brought a baby boy to a hospital. The baby still had the umbilical cord and placenta attached and a body temperature of 90 degrees, according to a probable cause statement.

The girl's father initially claimed the baby was his and had been dropped off on their porch by an ex-girlfriend.

He later told investigators his daughter had given birth to the boy and that his son was the father, a probable cause statement states. The girl's parents claimed they were not aware she was pregnant or that she was allegedly being sexually assaulted by her brother, according to the statement.

During questioning, the brother told police he had sex with his sister about 100 times but did not know she was pregnant, according to a probable cause statement. He also said he did not know how long it had been going on for, the statement said.

All three suspects are being held by the St. Charles County Department of Corrections, a jail official told NBC News Friday. Bail was set at $10,000 for the woman, $100,000 cash only for the man and $300,000 cash only for the teen, according to court records.

No attorneys are listed for them in online court records.

The baby, who was born premature, remains hospitalized, and the girl is in the care of relatives, St. Charles police Lt. Tom Wilkison told NBC News.