A man was robbed in an alley outside a busy restaurant. He was assaulted with a baseball bat that was left at the scene. There were bloody footprints leading away from him. He was treated by paramedics and taken to a hospital. Two witnesses saw the robbery. The suspect fled the scene. Which task should be done by detectives? A) take photographs of the scene including the bloody footprints B) secure the crime scene C) interview the witnesses D) collect the bat and the blood samples