Can I be fired for filing a sexual harassment complaint and should the employer contact me if the investigation is done?

You as an employee, have the right to file with HR a sexual harassment report. If your employer doesnt fix the problem, or worse , if your employer retaliates against you because of your report (ie firing or demoting you etc) , then your employer is in violation of the law and can be sued under the Civil Rights Statutes. That all said, You need to discuss this matter, in private, with counsel in your state before you take legal action, as laws can vary from state to state. Good luck and dont delay.