Today's show begins immediately following a press conference in Tulsa, Oklahoma, site of yesterday's mass shooting at St. Francis Hospital that left four people dead. According to the timeline police presented, one of the victims, Dr. Preston Phillips, performed back surgery on the suspected gunman, Michael Louis, on May 19. Louis had a follow-up appointment with Phillips on May 31, during which he complained of back pain. In between, Louis went to a gun store and bought a semi-automatic handgun. Then yesterday, Louis bought an AR-15-style rifle. CNN's Lucy Kafanov provides live coverage from Tulsa.

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