Would You Rat Out a Loved One?

— -- Police this week halted a potentially deadly bomb plot at a South Carolina high school after an 18-year-old senior was turned in by two very unlikely informants: his parents.

Ryan Schallenberger was arrested Saturday after his mother and stepfather alerted authorities that a package containing 10 pounds of ammonium nitrate, an easily obtained but highly explosive substance, had arrived at the family's home. It was later discovered that the straight-A student had plans for an attack he referred to as "Columbine III," according to police.

Schallenberger's parents, John and Laurie Sittley, could not be reached for comment, but local police acknowledged the heroism of the couple's decision to put the school's safety ahead of their family ties. Sam Parker, sheriff for Chesterfield County, said their decision saved lives.

"We all know that's a decision that would be very tough for any one of us to make as parents. We know they're heartbroken," he told ABC's "Good Morning America."

Family members turn loved ones over to the police all the time and for a variety of reasons, according Ann Adalist-Estrin, director of the National Resource Center on Children and Families of the Incarcerated, an advocacy group. Sometimes they go to authorities to protect innocent people they feel are threatened, sometimes to protect themselves, and sometimes to protect the very loved one who is to be arrested.

"Whenever a relative is in prison, family members feel guilt and a sense of responsibility even if they didn't personally turn that person in. Shame and stigma are the number one feeling for family members of arrested or incarcerated people," she said.

In Schallenberger's case, the alleged plan of attack was chilling. Police searching the family home found bomb-making materials, a pipe bomb and a detailed summary for a suicide attack.

"We applaud these parents and we're very thankful they chose to be concerned," Parker said. "They chose to get involved. We feel like they saved a lot of life in our county."

But saving the lives of others does not prevent family members from blame and second-guessing, sometimes suffering for years after their decisions put relatives in jail, or worse.

Bill Babbitt knows something of that guilt, shame and stigma.

In 1980, he turned his younger brother over to police on a suspicion that he murdered a 78-year-old grandmother named Leah Schendel in Sacramento, Calif. Convicted of the murder and sentenced death, Manny Babbitt was executed in 1999, one day after his 50th birthday.