To qualify for a U visa the person must show that he or she has suffered substantial physical or mental harm as a result of being the victim of criminal activity that occurred within the United States. The person must also show that they have information about these criminal activities and that it is, has been, or will be of use to federal, state or local authorities in the investigation or prosecution of the criminal activity.
There are a wide range of crimes that qualify for the U visa, so it is very important that an experienced immigration law attorney is consulted to assess whether or not the person qualifies for this visa option.