Here are audio files from the Pima County Sheriff's Department of 911 calls related to the shootings of U.S. Rep. Gabrielle Giffords and others on Jan. 8, 2011.

In the fourth file, an acquaintance of suspect Jared Lee Loughner tells 911 operators that the gunman tried to contact him the night before the shootings but gave no indication of what would happen the next day.

Launch the audio files by clicking on the nearby audio player controls.