An Arizona man was arrested in connection to the death of his 6-year-old son after he told investigators he poured hot water down the boy's throat to rid the child of a demon, according to a criminal complaint.

Pablo Martinez told police that he was performing an exorcism on the little boy Thursday because the child "was demonic and had a demon inside of him."

The boy's adoptive mother, Romelia Martinez, told detectives that her son "had been acting demonic" and her husband offered to give the boy and their other child a bath. She told police that she could hear gurgling coming from the bathroom and when she opened the door she saw Pablo Martinez holding the 6-year-old underneath the faucet in the bathtub, according to the complaint.

Romelia Martinez said she yelled at him to stop and he told her that "he had to do it." She then called a pastor and when he did not answer she called 911, telling the operator that at that time her husband was attempting CPR and poured cold water on the child.

Pablo Martinez told investigators he poured hot water down the boy's throat to try to "cast out the demon" after he witnessed the boy have an "unnatural fit of rage." He said the child was under the water for five to 10 minutes, the complaint states. The other child eventually left the bathroom in tears.

Pablo Martinez told investigators that he thought the hot water was working to cast out the demon. He was taken into custody on a first-degree murder charge.

Police found the child in a room propped against a pillow. He was rushed to the hospital where he was pronounced dead. According to the court documents, the boy had burn marks on 15 percent of his body, including his head, elbows, and forearms.

Authorities said Romelia Martinez is a member of the Pascua Yaqui Indian Reservation near Tucson. Pablo Martinez is not a member.

The reservation and the Pascua Yaqui Police Department did not immediately return requests for comment.

The child was a student at Lynn Urquides Elementary School in Tuscon, a school spokesperson confirmed.

"It is with deep regret and sadness that I inform you of the death of one of our students. Our counselors are available to help staff and any student who is struggling with death or other issues that may surface," the school said in a statement. "Our sincerest condolences go out to the family."