Yes, they can refuse to write an incident report. There is no law or other legal obligation requiring that any employer, including a school, write up incident reports about what happens at work or in the workplace. However, if necessary, you should be able to subpoena any other witnesses to appear to testify for you in an unemployment appeal--and if someone (e.g. the school police) did not witness the confrontation, then their report would essentially be valueless anyway, since it would not be based on actual personal knowledgeAsk the unemployment office about the appeal procedure and your right to subpoena witnesses. Even if you can't do it in an "in-house" appeal within the unemployment office, if you then escalate to appealing in court, you should be able to subpoena witnesses at that point.