new developments in the ugly emergency arrest caught on video in utah. the nurse who was taken into custody for doing her job is speaking out as the police department offers an apology. cnn's dan simon has more in salt lake city. [ screams ] >> reporter: the disturbing video comes from the inside of an emergency room. the woman screaming, a burn unit nurse being assaulted by a salt lake city police officer. >> please, sir, you're hurting me! >> then walk! >> no! >> reporter: the incident captured by police and hospital cameras happened in july. now the district attorney says he wants a criminal investigation. >> she doesn't -- >> reporter: university nurse alex wable said she was doing her job following hospital