New criminal background checks at the Austin Independent School District have uncovered hundreds of criminal histories.

The district refuses to disclose which teachers have criminal arrest records saying it has to find the legal balance between teacher privacy and a parent's right to know.

When Reagan high school student Nathan Manuel Mendoza attacked his teacher in October 2005 his teacher had no idea of his violent past.

Since then a system has been created that immediately notifies all school districts when a registered sex offender enrolls in class.

But when KVUE News started asking questions about the records of crimes committed by certified teachers, including administrators and substitute teachers the district refused to comply.

Even Superintendent Pat Forgione refused to talk with us. Instead, he referred us to the head of the legal department.

"This is new law, for the most part. And we really don't know under the open records act what is disclosable, and what is not. So out of respect for our employees in these situations, our responsibility is to send it to the attorney general and let him give us an opinion," said AISD general counsel Mel Waxler.

The district would disclose that the Texas Department of Public Safety searched 7243 records district-wide for arrests and or convictions. 36 of those records indicated a felony, and in all 637 records indicated a criminal history. The district says it notifies principals if any of its school employees have a felony history. It's up to the principal to decide if anyone else at the school should know.

Of those 637 records only one teacher, a substitute, has been removed from the classroom.

"In this particular case there was evidence that there was some activity that was related to the potential for or injury to a child or an elderly person or an injured person. This was nothing that happened on campus," said Waxler.

According to a new state law anyone convicted of felony assault or a felony sex crime, must be fired.

The district says it only automatically terminates employees that commit those types of crimes.

DPS started notifying AISD in January about the criminal histories of its certified educators.

It found an assortment of crimes.

"We have some DWIs, some theft by check, we have criminal trespassing. We do have a couple [felonies], and these we'll have to look at carefully. There's some family violence, assault by family violence issues," said Pamela Hall, an AISD human resources employee in February.

But since then the district is no longer willing to give details of the crimes committed by its teachers.

Many parents believe they have a right to that information.

"When you become a teacher, I don't think you have the right to keep something like that private," said parent Molly Urrabazo.

"To be honest if there's a felony conviction on a teacher that's teaching my child, I would want to know that. I think if it's a misdemeanor, it's a little different. But yeah, that, that would be disturbing to me if that wasn't disclosed," said Holly Rios, another parent.

 The district refuses to guarantee that more convicted felons won't end up in the classroom.

"Will the district hire anyone else who has a felony criminal history? I think the HR department will look at when it occurred, what the nature of it is. If it's sexual or assaultive I think I can fairly say, absolutely not. But there are lots of circumstances in which I would have to say, that would be up to the informed professional judgment of HR," said Waxler.

Some retired teachers say the district has no business hiring teachers with a criminal past.

"They certainly shouldn't hire somebody that has a questionable past, and let them work with our children," said former teacher Martha Foster.

But unless the attorney general tells the district otherwise parents will have to rely on the district to look out for their children.