JONESBORO, Ind. — Authorities in northeastern Indiana say they believe a 17-year-old boy who killed his 13-year-old girlfriend before fatally shooting himself in February also fatally shot an 81-year-old man during an attempted robbery in January.

The Grant County sheriff's office says the state police laboratory determined the gun used by Corbin Page to kill Alainee Byer and himself at her home in Marion was the same gun used in a shooting at a Jonesboro home that killed Gene Thompson and wounded another man.

Investigators say both teens were at the home for the attempted robbery. Two 17-year-olds who authorities say confessed to assisting Page are facing charges in juvenile court.

The Marion Chronicle-Tribune reports Jonesboro police say interviews in the investigation led to at least 10 other theft and drug-related arrests.