A Phoenix police officer shot to death an unarmed black man during a struggle and authorities said the officer believed the individual had a gun, in the latest fatal incident amid national turmoil over the policing of black communities. The Phoenix Police Department said Rumain Brisbon, 34, was sitting in a black Cadillac SUV outside a convenience store on Tuesday evening, and that two witnesses told the officer the occupants of the vehicle were selling drugs. With police forces across the country under increased scrutiny over killings of unarmed black men, Phoenix police said in a statement that its officer...