Judge: Life sentence will stand for convict who killed as a juvenile

CHICAGO -- David Biro, convicted for the 1990 double murder of a pregnant Illinois woman and her husband that he committed when he was 16, will serve out the remainder of his life sentence after a judge denied his petition for a new sentencing hearing in the death of the unborn child.

WATCH: "48 Hours:" Road to Redemption

A Cook County judge ruled Thursday that Biro's "discretionary" life sentence for the intentional homicide of an unborn child was not covered by a 2014 state Supreme Court ruling granting new sentencing hearings to people given mandatory life sentences for murders committed when they were under 18, reports CBS Chicago.

That 2014 Illinois state Supreme Court ruling was based, in turn, on a 2012 U.S. Supreme Court case that declared mandatory life sentences "cruel and unusual" when issued to convicts who were children when they committed their crimes, the station reports.

Biro was a 16-year-old high school junior when he killed Nancy Langert, who was pregnant, and her husband Richard in their suburban Chicago home. Even though the state Supreme Court ruling leaves Biro eligible for a new hearing on his mandatory life sentences for the couple's slaying, the judge's decision this week concerning the death of the unborn child virtually ensures he won't be freed from prison.

Biro, now 42, was not in court Thursday. His lawyer his vowed to appeal.

"48 Hours" investigated the Biro case in the episode, "Road to Redemption." In the episode, Nancy Langert's sister, Jeanne Bishop, says that her search for answers in the murders led her to contact Biro.

She says she has forgiven Biro, and now visits him in jail.

"Does he deserve another chance? Yes. I think he does," Bishop told the broadcast.