DENVER — A Colorado woman charged in the death of her 7-year-old son told a fellow inmate that the boy died in July, months before his body was discovered encased in concrete inside a Denver storage unit, according to court records unsealed Tuesday.

Authorities have released few details about the death of Caden McWilliams since his body was discovered in December.

Records involving the arrest of his mother, 43-year-old Elisha Pankey, had not been available to the public until Tuesday. She is charged with child abuse resulting in death and with the abuse of a corpse.

A woman whose name is redacted in court records told police that Pankey said she and her husband sometimes forced the boy inside an animal carrier.

The woman said Pankey told her that sometime in July they kept him in the carrier overnight despite his cries of being thirsty and hot.

Pankey said the boy was dead by morning and she believed he had suffocated, the records state.

The woman told police that Pankey said she and her husband took the boy’s body — still inside the animal carrier —to the storage unit, poured concrete over him and wrapped the carrier in plastic trash bags.

Leland Pankey, the boy’s father, has remained in jail since late December on an outstanding warrant. He has not been charged in connection with McWilliams’ death.

The records show police began investigating the family in mid-December after Pankey reported that her husband had choked and threatened to kill her.

The records portray a chaotic life, with both parents living in hotels. McWilliams last attended school in late May. His mother unenrolled him from Denver Public Schools in the fall of 2018 and said he would be home-schooled.

She told investigators that Leland Pankey took their son and daughter to live with him in November and had been sending her threatening text messages. Within a week, police in suburban Aurora arrested Leland Pankey for outstanding warrants in the metro area.

But they could not find McWilliams or get more information from his parents.

During a search of Elisha Pankey’s hotel room, police found a business card with a unit number from a public storage facility in Denver. They also found heroin and took the woman to Arapahoe County jail on suspicion of drug possession, the records state.

Denver police opened the storage unit and found a large chunk of cement inside an animal cage that had been wrapped in plastic sheeting.

Investigators say they discovered a decomposed child’s body in the cement but could not immediately tell if the remains were those of McWilliams.

The Denver coroner’s office later identified the body but could not determine how the boy died. An autopsy found signs that McWilliams was severely emaciated and evidence of injuries to his head, chest and limbs, some of which showed signs of healing.

Pankey has not entered a plea and is due back in court April 2. She is represented by the state public defenders’ office, which bars its attorneys from commenting on individual cases.