A former Sandy Springs police lieutenant was fired for "good cause" for her disregard of police policies, not because of any personal bias against her, the city attorney says.

Trudi Vaughan said Tuesday said she was fired unfairly for decisions that had been authorized by her superiors, or for doing things that male supervisors had done without being disciplined.

She said she plans to contest her dismissal and file a discrimination lawsuit.

She says she was targeted because she is female and gay.

"Other white, heterosexual males have done the same things I've done," she said. "None of them have been disciplined. None of them have been fired."

City Attorney Wendell Willard dismissed her allegations. "As far as her lifestyle, that had nothing to do with the disciplinary action imposed," he said. "It was known of her lifestyle when she was employed by the city."

Acting Chief of Police David Bertrand fired Vaughan July 16 after concluding she had "displayed a disregard" for city rules and regulations.

He cited the findings of an investigation completed July 10, which found Vaughan failed in her supervisory duties when she allowed 20 of her officers to shoot weapons they weren't trained to use and ride all-terrain vehicles without helmets at a training exercise on city time.

Bertrand also cited investigation findings that Vaughan had directed officers to file backdated or false documents and used officers who were on-duty to fill side, traffic enforcement jobs that she coordinated.

In the termination letter, Bertrand described the violations of city rules as "egregious."

The investigation began within the department, after several officers approached Bertrand, then a police major in charge of administration, and said they were disturbed by what was happening.

An internal investigation into the allegations was turned over to an outside group, U.S. ISS Agency, after city officials said they discovered more widespread problems.

Vaughan, 40, says Bertrand dislikes her personally, and pursued an investigation against her because of her gender and sexual orientation. "It's because I'm a female in a position of authority."

The investigation report found "no evidence" that Bertrand had "issues with gay females in position of authority."

Before she was fired, Vaughan supervised the special operations officers, including narcotics, traffic enforcement, anti-gang and SWAT teams.