Lisa Luviano, the mom of a 4-year-old student at Northgate Crossing Elementary School in Spring, Texas, told ABC News station KTRK-TV that her daughter came home from school with a sticker featuring a starry-night like design.

“She said, ‘It’s a sleeping sticker,’ and I asked her, ‘Where do you get this?,'” Luviano told KTRK. “She’s like, ‘Well, my teacher gives it to me for sleeping time.'”

Luviano said after hearing her daughter’s response, “I had straight anxiety just thinking about what’s going on with the school.”

Luviano said she believes the sticker placed on her daughter was melatonin, a hormone that plays a role in sleep, according to the National Institutes of Health.

The day after the conversation with her daughter, Luviano said she went to the school to report the sticker. She told KTRK she believes her concerns were not immediately addressed.

ABC News obtained an email that parents of Northgate Crossing Elementary students say the school’s superintendent sent out saying that the two teachers and two paraprofessionals involved were removed from the classroom. According to the email, the employees were placed on administrative leave as police investigate the allegations.

No charges have been filed against school employees.

“We send our kids to school knowing that our kids are going to be safe here. We trust our teachers,” she said. “For that to happen. That’s unacceptable.”