This person is salaried employee. Has worked over a year. Is rude, arrogant, loud and bossy when speaking to fellow employees. At first she had gall bladder attacks and was always in pain. She was to have an operation within the first year of hire. After six months she boards a plane for vacation in Jamaica. She was told not entitled to any vacation for one year, but she "knew her rights and was going". We scrambled for a week.

Later her gall bladder problem disappeared. She kept taking time off for regular doctor appointments. Again another problem occurred. She was always in pain with stomach. She had mammogram and was told of some kind of shadow. One morning she came to work with a doctors note "off for medical reasons." Two other people in the office at two different times have seen her working in a retail store. She was fine. After her first ten days off we found another note pasted to the building to say two weeks more off. She has left a message to say she will be in to pick up her things. We need to fill her position and we are not sure how to go about doing so.

How can we prove misconduct if we can fire her?