The two victims were found near the Aspire Academy near 15th Avenue and Mount Street in Gary.
The girl, who the coroner's office describes as a very young-looking teenager, was shot twice in the head.
Neither victim had I.D., and the man who was shot is hospitalized and hasn't been able to talk to investigators.
The girl is described as 5' 2", 106 pounds, wearing black jeans, red shirt, black and gold coat with Tweety Bird, Sylvester and Lot29 patterns on the coat. She has a tattoo reading, "Shay" on her lower back and right arm, and a drawing of Winnie the Pooh on her arm, the coroner's office said.
