I suspected someone who robbed me while we were alone. Thank you.

If money is lost, one must first ascertain where it was lost. It is not permissible to accuse someone of theft merely based on suspicion if they are known for their good conduct, because accusing them without evidence is forbidden. However, if a person is certain that this individual is the thief, or if the person has known prior offenses, then one can speak to him or send someone to persuade him to return what he took, and to warn him of Allah's punishment. If he refuses, it is not permissible to take anything from him or to refer his case to the judiciary except with lawful evidence proving his theft.