The department's Inspector General office investigated the claim, which stemmed from the events of April 23 and 24. An investigator interviewed the inmates, the staff and Newkirk.
According to the investigative report, which the department released Wednesday, here's what happened:
The inmate, who at the time was 16, admitted flooding the toilet inside his cell about 6:15 p.m. April 23. When staff shut off the water supply, he broke a fire sprinkler on the ceiling, flooding his cell and surrounding cells in a dorm named Wildcats.
The boy said he was upset a staff member had failed to address some of his concerns, the report said. It didn't specify what the concerns were.
Inmates were relocated while staff cleaned the mess. Newkirk said someone at Cypress Creek called the place where he was staying about 11:15 that night to report what had happened.
He went to the facility and asked that the boy who caused the damage be brought back to help clean, Newkirk told investigators.
From there, accounts vary significantly.
Newkirk told investigators the boy who flooded the dormitory used foul language, threw a squeegee at him and threatened him with a clenched fist.
In response, Newkirk said he placed the boy's arms behind his back and took him to the floor, all in an effort to calm him.
The boy said Newkirk, unprovoked, threatened him, cursed, placed him in a headlock, punched the right side of his face with a closed fist and then pushed him into a wall, cutting his head.
Two fellow inmates corroborated that version of events. One employee witnessed the headlock and another saw Newkirk push the boy, the report says.
Two staffers contradicted Newkirk's claim that the boy was the aggressor. The medical staff confirmed the boy required medical attention.
The Inspector General substantiated allegations that Newkirk used improper and excessive force, failed to report what happened, as is required, and bragged about what he had done later during a staff meeting, the report showed.
The report also cited youth counselors Kent Clark and Mario Muniz and acting shift supervisor Johnny Estevez for failing to complete an incident report, despite their knowledge of what had happened.
The supervisor was suspended, Cypress Creek said, while the other staffers were reprimanded.