(By The Associated Press) DALLAS, Aug. 1.—Police were ex erting every effort today to iden tify the man who killed Sammie Bakal, 26-year-old driving range employee, with a rifle here last night. Bakal was sitting on the front porch of his former wife’s home when his assailant drove up in an automobile and fired three shots at close range. Miss Sylvia Borkon, Bakal's for mer wife, said she had never seen the rifleman before. She expressed her belief she would be able to identify him if apprehended. Police thought if possible that Bakal was a victim of mistaken identity. They said it was likely the shots were intended for anoth er man.