The parents of a 4-year-old girl who drowned in a Spokane apartment bathtub this weekend appeared in court Monday facing allegations they heavily abused her and were responsible for her death.

Father Jonathan Lytle, 28, and stepmother Adriana Lytle, 32, were both being held on $500,000 bond in a case one sergeant described as "beyond abuse."

"There was the use of a electric dog training collar used on this girl," Sergeant Joe Peterson of the Spokane Police Department told KXLY. "And what's even more dreadful is that isn't even nearly the worst of it."

The girl, who had been living in the apartment since August, was also bitten by her stepmom, burned and beaten with spoons and belts, court records and officials said.

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The two were arrested Saturday night after the father brought his unconscious daughter to Deaconess Medical Center with a wide range of bruising and signs of long-term abuse.

It started when the daughter, who was reportedly developmentally disabled, had been ordered by her stepmom to wash her urine-soaked items in the apartment bathtub while standing in it, police said.

The stepmom said the child frequently wet herself and she handled it by submerging her in water and telling her to do what she did that night.

"My house, my rules," the stepmom reportedly told police during an interview, according to KXLY. "You're not at mommy's house anymore."

In this instance, stepmom Adriana — who had been cooking to celebrate her one-year wedding anniversary to father Jonathan — said she went back into the bathroom and found the little girl unresponsive, lying on her back in the bathtub filled with water and urine.

The stepmom reportedly said she tried to perform CPR "using her hands and feet," until the father came to assist — but he soon left the room to go smoke a cigarette.

After Adriana said to Jonathan, "We might have killed her," they took the girl to Deaconess Medical Center, where she was pronounced dead, officials said.

Doctors informed investigators soon after the girl's arrival. Once they got an opportunity to see the child for themselves, investigators saw the girl had been the victim of long-term abuse.

The girl had injuries "from her feet to the top of her head," Peterson said.

"This is the worst case I've ever seen and my detectives feel the same," he said. "It's probably the worst case of abuse that any of us in hundreds of combined years in this unit have ever seen."

"It's beyond abuse ... it's abuse by torture."

After being read his rights, the father told police that the girl kicked her stepmom in the chin and the stepmom responded by biting the girl, according to court documents.

"They had concocted a story the child fallen down one time to cause these injuries," Peterson told KXLY.

Investigators will now have to wait until the autopsy is finished to determine the full range of injuries the child sustained.

The father reportedly told investigators that the girl's biological mother asked if she could live with him and the stepmom for a month, but never tried to to regain full custody of the girl.

A second child in the apartment, an eight-month-old boy, was taken and placed in foster care.

KXLY and The Associated Press contributed to this report.