Can a supervisor ask an employee what they wrote in their accident report?

Your question is vague and therefore difficult to answer fully. If you do not feel this answers your question, please ask more explicitly or provide more details on the discussion page for this question.

I am assuming you are referring to a workers compensation situation where the employee is claiming against the employer. The employer has a right to know what you are claiming. If you feel that your supervisor is attempting to harass or pressure you because of what you wrote in a workers compensation report, you should consult an attorney.