A second grade teacher at Denver's Oakland Elementary School is under investigation after allegedly using Scotch tape on the mouths of two of her students.The mother of one of the boys told 7NEWS that the other boy was whistling in class Thursday and the teacher told him to stop. He didn't, so the teacher allegedly taped his mouth shut, she said.She says that's when her son, DeUndre, started laughing, and that the teacher then taped his mouth shut as well."I was shocked," said Gina, who asked us not to disclose her last name. "It was like no, not in these days and times. A teacher is not going to touch your child and tape them, and basically assault your child."Gina said her son suffered a nose bleed after the incident. She doesn't know if it was related to the taping or not."I don't believe a teacher should be able to cut off a child's airway to where he just has to breathe out of his nose," Gina said."This is not behavior that we condone," said interim Denver Public School's communications director Lisa Schiff. She said there are more appropriate ways to discipline children. "Talk to the students about their behavior privately. If it continues, send them to the (principal's) office."Schiff said some schools have time out procedures for children who exhibit distracting behavior in class. She adds that some schools ask students to write a paragraph about their misbehavior and why it was wrong. She said in that sense, it's a learning experience.Gina agrees with that. She said if her son is a disciplinary problem, she wants the school to call her.District officials won't say if the teacher will be disciplined. They say that's a personnel issue. They did say that both the teacher and the two boys were back in class Friday.