Two people have been arrested in what authorities describe as a twisted, gruesome case of abuse involving a child's corpse hidden in a broken-down car, a starved baby living on water and a sheltered teenager impregnated by her stepfather.

Jondrew Lachaux, 39, and Kellie Phillips, 38, turned themselves in after the three children were discovered, North Las Vegas police said.

The two face child abuse charges. Lachaux is also charged with concealing evidence after the toddler's badly decomposed body was found in the garage.

According to court documents, the man and woman took five of their children on a trip to Oakland, California, eight months ago. The couple left behind two daughters — a teen and a sickly 3-year-old toddler — in their suburban Las Vegas home because the rental vehicle was full.

The teen is Phillips' biological child and Lachaux's stepdaughter.

Authorities say Lachaux reportedly impregnated the teen, who gave birth at home without any medical care to a now 4-month-old girl.

She struggled to care for herself while pregnant and her 3-year-old sister who had medical problems while they were home alone. But the teen said she was too scared to call for help even after the food and medication left by their mother ran out.

"The totality of evidence is leading investigators to believe she was almost a prisoner in her home," police Sgt. Chrissie Coon said. "Fugitives can psychologically confine their victims without physically being present."

The case first unraveled on April 1.

The teen was seen at McCarran International Airport with a very sick baby. The infant was hospitalized in extremely critical condition for severe malnutrition and hypothermia from surviving on watered-down baby formula.

In an interview with police, the teenager described abuse at home in detail, claiming Lachaux raped her without her mother knowing.

For the last five years, the family had lived in North Las Vegas, but the group of children rarely went outside and was homeschooled. The teen told police she has had braces on from five years ago but hasn't seen a dentist since.

In late March, she said her stepfather came home to hide her sister's corpse and then kicked her out of the house in fear that her mother would find out about the pregnancy. She survived for a few days homeless in public places, including at the airport and on the Las Vegas Strip.

The teen said the 3-year-old sister apparently had trouble breathing and died about a month ago. She called her parents for two weeks before Lachaux called back to learn of the death.

Lachaux and the teen apparently hid the badly decomposed body in the back seat of a broken-down Mercedes in the garage. The corpse was leaking fluids but was concealed in a box surrounded by blankets, plastic bags and pizza boxes, according to court records.

The coroner's office said it has not yet positively identified the body or the cause of death.

The teen is now being held in juvenile detention on a child abuse charge.

The other five children -- ages 1, 3, 4, 7, 8 and 9 -- were found with Phillips in good health and have been put in protective custody.