First, if your case is a criminal case and you want to investigate the criminal responsibility of the other party, you need the public security organ to issue a power of attorney for injury identification before you can conduct injury identification. Because the criminal case of injury is a criminal responsibility pursued by the state public authority, not a civil case, the civil legal responsibility of the other party can be pursued by itself, and the nature and requirements of the two responsibilities are different.
According to the law, after accepting a case of injury, the public security organ shall issue a power of attorney for injury identification within 24 hours, informing the victim to go to the designated appraisal institution for injury identification.
Second, if your case is a civil case, that is, the other party has done harm to you, causing harmful consequences, you can entrust a qualified disability appraisal institution to conduct disability appraisal, and you can directly file a civil lawsuit without a power of attorney from the public security organ, asking the other party to bear civil liability for compensation, such as a civil case of personal injury compensation in traffic accidents.