"48 Hours" investigates mysterious murder of teacher gunned down

The mystery of who murdered a Pennsylvania teacher remains unsolved more than a year after she was killed. Rachael DelTondo, 33, was gunned down in a driveway of her parents' home in Aliquippa, just outside of Pittsburgh. There are multiple leads but no arrests. "48 Hours" correspondent Erin Moriarity joins "CBS This Morning" to preview her report, "What Happened to Rachael?" Watch Saturday, May 18 at 10/9c on CBS.