The mother of a 9-month-old girl missing since last week told investigators that she and the baby’s father tied their daughter’s corpse to a sandbag and dumped it into Lewisville Lake, according to an arrest affidavit.

The father, 20-year-old Alandus Weaver, was arrested over the weekend on a charge of tampering with evidence. Police said today that the mother, 19-year-old Tamaira Creagh, who faces the same charge, was booked at Dallas County jail today.

Police were at the lake today searching for the remains of Daisja Weaver, who was reported missing by her parents late Tuesday. Creagh had told police an intruder entered their apartment and tried to sexually assault her before fleeing with Daisja. She said her attacker said nothing and could not provide a detailed description of him.

From the beginning, investigators have expressed skepticism about the reported kidnapping, saying that the parents provided conflicting accounts.

As early as Wednesday – hours after the purported kidnapping, detectives read both parents Miranda warnings advising them of their rights to remain silent, according to the newly released affidavit.

But police released the parents as witnesses and continued combing the area with dogs in hopes of finding the child.

On Saturday, detectives met again with Creagh, who was accompanied by an attorney.

Daisja Weaver

Police say she told them Weaver picked her up from work on June 8, and told her that the baby was home alone. He said he had given the child a bath.

When they arrived home, Creagh told investigators, she found the baby on the floor naked, wrapped in a towel. The baby had no heartbeat and was cold, she said.

The mother said Weaver performed CPR on the baby for nearly 30 minutes without success. When she asked Weaver what happened to the child, she told police, he became threatening and violent.

JIM MAHONEY/DMN

A Denton County Sheriff's Department boat takes part in the search effort for missing baby Daisja Weaver Monday near the I-35 bridge over Lewisville Lake.

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She said he told her they had to stick together and report that the baby had been kidnapped. The following day after she got off work, she said, Weaver made her drive to Lake Lewisville with him. He stopped at a bridge and dropped the girl into the lake.

She told police that she was afraid of Weaver and that she is 6-months pregnant with his baby, according to the affidavit.

WFAA-TV's Rebecca Lopez contributed to this report.