By Jay Gormley & J.D. Miles, CBS 11 News

MCKINNEY (CBSDFW.COM) – Carla Mullendore has been praised and persecuted since she reported sexual abuse allegations against McKinney chiropractor Dr. David Russell.

The former instructor at Taylor Dance Center in McKinney said she’s had parents send her messages expressing their thanks. At the same time, though, she said she’s incurred anonymous emails that “just keep repeating, ‘I know what you did.”

“Morally, it’s the right thing to do,” Mullendore said of reporting the allegations to the police. “It’s disrupting a lot of lives, but I have a responsibility as an adult and a parent.”

Russell is charged with sexually assaulting an 18-year-old woman who was 16 at the time and another girl who is 13. McKinney Police are also investigating whether he sexually assaulted two other girls, although no charges have been filed.

Court documents show Russell worked as a volunteer at the Taylor Dance Center, teaching stretching and conditioning. Police say the alleged sexual assaults took place at his clinic while treating the two girls for groin injuries.

On Monday, CBS 11 obtained an email sent by the owner of the Taylor Dance Center, Suzan Taylor, to dozens of parents. In the message, she writes, “To be quite clear, I believe that these allegations to be 100% untrue.”

While the alleged sexual abuse was taking place, Russell and Taylor were in a long-term relationship, the doctor’s attorney said.

“They’re not married. They’re certainly not holding themselves out as husband and wife, but they’ve been an item – boyfriend, girlfriend – for almost a decade now,” said Todd Shaprio, Russell’s Plano-based attorney.

Shaprio replaced the doctor’s original lawyer, Collin County-based Raf De La Garza, over the weekend. Shapiro said Monday that the chiropractor invested money to help build Taylor a new studio.

In her email to parents, Taylor expresses concern that the allegations could end the project.

Mullendore, who was employed by the Taylor Dance Center for 16 years, said a teenaged student approached her and told her of the alleged abuse.

“She wasn’t comfortable with what happened and she was concerned about it and just asked us what we thought,” Mullendore said.

Soon after, Mullendore learned of a 13-year-old with the same story. The allegations outlined in a police affidavit say the same thing. Mullendore adds that she did her own research about chiropractic procedures before she alerted police.

“It certainly didn’t sound normal to me,” she said.

Mullendore said she approached authorities in February, but became frustrated that nothing was done in the months that followed. McKinney Police did not respond to a request for comment, but police affidavits allege one of the assaults happened after Mullendore came forward.

Russell was first arrested on Oct. 28 and again on Nov. 4. He was released on $100,000 bond each time.