A Florida special education teacher and two aides are charged with abusing children with autism by blowing whistles into one’s ears and locking them in dark bathrooms.

The Northwest Florida Daily News reports that teacher Margaret Wolthers surrendered Tuesday to Okaloosa County sheriff’s investigators to face aggravated child abuse charges. Aides Diana LaCroix and Carolyn Madison had already surrendered.

Sheriff Larry Ashley said the women abused three children between ages 8 and 10 from September to November. He said all three children were locked separately into a bathroom with the lights off for up to 90 minutes. The children reportedly would "scream and cry" when placed in the bathroom.

“Investigators say on different occasions the teacher and aides ‘intentionally and maliciously’ blew a whistle in the ear of a child with a low sensory auditory threshold who wore earphones to protect him from loud noises,” the department said in a news release, according to the Miami Herald. “They also threatened him with a whistle.”

Wolthers, LaCroix and Madison allegedly blew the whistle within seven inches of the child’s ear.

“This was done while holding the victim’s arms down keeping him from protecting himself by covering his ears,” an investigator wrote in the warrants.

The women said they were disciplining the children and felt the practices acceptable.

“The principal in that incident confirmed that the school policy does not allow for seclusion without supervision as a form of punishment and is prohibited,” Ashley said in a press conference. “Likewise, holding a student captive while blowing a whistle in their ear is not an acceptable form of discipline or proper protocol of correcting this behavior.”