Nearly 50 years after a woman’s body was discovered inside a cardboard box in an Indiana cornfield, investigators have finally learned who she was. The breakthrough closes one of the region’s longest-running mysteries, ending decades of unanswered questions that began with a shocking discovery in 1976. The victim has been identified as Jane Hart, who was born in 1906 and was 69 years old when she was killed. She had been shot in the back of the …