The four people killed in a mass shooting at a hospital campus in Tulsa, Oklahoma on Wednesday have been identified as Dr. Preston Phillips, 59, sports medicine specialist Dr. Stephanie Husen, 48, Amanda Green and William Love, still unclear whether they were patients or staff members.  

The gunman, who died of a self-inflicted bullet wound, was identified as Michael Lewis.  Lewis allegedly bought an AR-15 type assault rifle the same day he went to the St. Francis Health System campus to kill the doctor he blamed for back pain he felt after surgery, authorities said on Thursday. 

Police said Lewis shot indiscriminately when he reached the second floor of the building.

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