A 6-year-old girl whose adoptive parents are accused of her murder was found dead inside a dog cage with duct tape covering her mouth and nose, her sister told officials.

The sister’s account was in a criminal complaint filed Friday in Honolulu circuit court.

The girl provided the details to a Honolulu police detective Nov. 5, nearly two months after Isabella Kalua was reported missing by her parents, Isaac Kalua, 52, and Lehua Kalua, 43, according to the complaint.

The couple was arrested Wednesday on suspicion of second-degree murder.

In an interview with police, Isaac Kalua denied being involved in Isabella’s disappearance, according to the complaint.

The sister, who was identified in the documents only by her initials, was also adopted by the Kaluas.

The events she described took place roughly two months before she spoke to police, the documents say. She said she saw Isabella duct-taped and inside the cage in the middle of the night.

At the time, Isabella wasn’t breathing, the sister told the detective.

Lehua Kalua removed Isabella from the cage and put her in a tub filled with water “to see if she would wake up,” the sister told police, according to the documents. “It did not work.”

Her parents told her to “keep a secret” that Isabella didn’t wake up, the sister said.

She told the detective that her sister was dead, though she didn’t know what her parents did with her body, which hasn’t been found.

Isabella was put in the cage because she would “sneak around at night and want to eat because she was hungry,” the sister told authorities, adding that Lehua Kalua had duct-taped Isabella “plenty of times.”

It isn’t clear if the Kaluas have lawyers. Their case was referred to the Honolulu public defender’s office, which declined to comment Friday.

William Harrison, a lawyer and family friend who has previously spoken on the couples’ behalf about Isabella’s disappearance, said in an email Friday that he had just learned about the allegations and is not representing them.

“Of course I am extremely saddened,” he said.

According to the complaint, Lehua Kalua told authorities that the last time she saw Isabella was the night of Sept. 12, when they ate dinner together. The next morning, after finding Isabella’s bed empty, police were dispatched to the Kaluas’ home to take a report that she was missing.

The report prompted a search effort that included hundreds of volunteers scouring the Waimanalo area of Honolulu, where the family’s home is, but authorities said Wednesday that they now believe the account provided by Lehua Kalua is false.

In addition to Isabella, who was adopted in 2018, and her biological sister, who was adopted in 2009, the Kaluas took in two more of their siblings — one in 2018 and another last year. The childrens’ biological parents are described in the complaint as homeless in the Waimanalo area.