U visas. 10,000 visas per year are available to those who have suffered substantial physical or mental abuse as a victim of a qualifying criminal activity that occurred in the U.S. There are other requirements and prior to filing with the US CIS a certifying officer must sign a certification confirming that the applicant has been a victim of a crime and is willing to cooperate with the authorities. Spouses and children of the principal are also eligible. There is a backlog and U visa applicants must wait years until a visa number becomes available. The U visa is valid for four years and after three years in U status the applicant is eligible to obtain his permanent residence.