A U.S. State Department law enforcement agent from the mainland was arrested for fatally shooting a man in his 20s early this morning on Kuhio Avenue in Waikiki, sources said. Honolulu police identified the alleged shooter as Christopher W. Deedy, 27, and sources who asked to remain anonymous confirmed that he is a federal agent who was off-duty at the time of the shooting. The victim was identified by family and friends as Kaneohe resident Kollin K. Elderts, 23, a Kalaheo High School graduate. A State Department spokeswoman in Washington, D.C., said only, "We are aware of the incident and we cannot...