“Do people with multiple personalities commit crimes?”

One's criminogenic history may or may not be solely related to their personalities . There are lots of factors to consider when treating a criminal.

This is too vague to answer. A lot of people commit crimes, not just people with multiple personalities. This isn't an actual medical diagnosis. It was changed years ago to Dissociative Identity Disorder which is a response to severe trauma. Most vets have this diagnosis, and it is also more common in women. You basically detach from reality. More often individuals who use drugs commit a great deal of crime, or others with personality disorders. Crime is not specific to the personality disorder you asked about.

Yes they can if not in therapy.