SPOKANE VALLEY, Wash. -

A Spokane Valley substitute teacher accused of assaulting elementary school students Thursday has a criminal history, including a DUI arrest just last month.

46-year old Matthew C. Deryan was arrested early Friday morning on 4th degree assault and unlawful imprisonment charges. Deputies say he put his hands on several students and swore at them, then refused to let some of them leave the Trent Elementary School classroom.

One student told deputies he was working in the hallway and heard commotion in the classroom. He said when he walked into class, he thought he heard someone get slapped. He said students were cryintg and upset and when he tried to leave the classroom, "Mr D stopped him at the classsroom door by grabbing his right arm with both hands and push[ing] hard on the veins on top of his forearm." Then, "Mr. D pushed him hard, about a foot off the ground, slamming his back against the door."

When deputies interviewed the student nearly two hours later, he still had the red marks on his arm and red marks across his shoulders and back.

Another student told deputies Deryan smelled like alcohol and cigarettes. That student says Deryan slapped his hand so hard, he made the student cry. When that child tried to leave the classroom, "Mr. D blocked that door, then locked the door and yelled at him." Then, the student says Deryan lifted that student off the ground and threw him into the door.

Several students say Deryan was swearing at them in English and Spanish. Many were crying; some tried to crawl out of the classroom by crawling through Deryan's legs as he blocked the door.

Deryan denies the allegations, saying the students were upset because they were given pink slips.

Deryan's criminal history reveals serious allegations, including a protection order that prohibited him from seeing his own children. He was also arrested for DUI in Kootenai County last month and was accused of altering court documents in Spokane.

So, why was he allowed in the classroom?

"He had a legitimate substitute teacher certificate, he had been fingerprinted and was cleared by both the WSP and the FBI," said East Valley School Superintendent John Glenewinkle. But, Glenewinkle says the state only allows those background checks to be done when the teacher is hired; after that, it's up to the teacher to disclose any criminal behavior on an annual basis.

While Deryan sits in the Spokane County Jail with $20,000 bond, the district says it's doing what it can to help the traumatized students recover.

"We've mobilized our crisis counseling team to talk to kids who need that, so we will get through this," said Glenewinkle.

The district says Deryan is no longer welcome at any of its schools.