What are my options if I was accused by a patient of stealing her pain meds and am I obligated the investigator wants me to come in for interview?

I am a Phlebotomist. A new patient called the cops and my job stating that I stole her pain meds I absolutely did not. She filed a police report. The investigator spoke to my boss who told her he believed me and did not think I would ever do such thing. She also called me and wants me to come in for an interview. I am not comfortable with any of this for I am innocent. I told her I would not speak to her without an attorney but I don't believe I should have to pay for one just to be interviewed. I thought I would tell her that and then if they find a way to charge me then I would get an attorney. I just don't want to make matters worse. I have never dealt with the police other than being pulled over a few times in my life and this is very scary and can be serious. I am beside myself that they are even looking into this on her word although there is proof I was in her house because I was scheduled to be there.