May I become a police officer with an HIV diagnosis? The police in my area already know my status.
It is highly doubtful that any organization today would try to impose such a restriction, even among the police. The final answer, however, is with the department you intend to join and their eligibility requirements. Should they try to exclude you for that reason, I would encourage to consult with an attorney at your local, federal EEOC office (Equal Employment Opportunity Commission).
Good luck, Jacques