A couple from Marietta traveled to a small Georgia town in the hopes of buying their dream car, but the whole thing turned into a nightmare, and instead of returning home, they were murdered.

It is a horrible story, all the more chilling because the couple looked, from their photos, like typical grandparents who lived in an ordinary brick home with a bright American flag outside.

I wondered how such terrible things can happen out of the blue to everyday people. Is there a theological explanation?

Flannery O’Connor could have easily answered that one. In her novel “The Violent Bear It Away,” a young man named Tarwater begins hearing the voice of a stranger in his head, tempting him to stop believing in Jesus—and assuring him the devil isn’t real. Once he succumbs to that voice, he goes on to do terrible things.

O’Connor was horrified when some readers had trouble identifying the voice and noted in a letter, “I certainly do mean (the voice) to be the Devil.” She wanted to be sure “the Devil gets identified as the Devil” in her stories rather than as a psychological tendency.

Oh, I know many people will assure me she was wrong, and there’s really no such thing as the devil. They’ll say the demons mentioned in the Gospels are just mental illnesses and remind me that back in Jesus’ time modern psychology didn’t exist, so he didn’t know about various complexes and delusions.

But Jesus was divine and certainly didn’t need to study psychology to understand human nature. And we know he believed in the reality of Satan, since he spoke with this tempter in the wilderness—and he wasn’t talking to himself. We are also told that Jesus caused demons to exit a man and enter a herd of pigs.

“You can’t cast a medical disorder out of a man into a pig,” wrote Paul Thigpen in an excellent new book, “Manual for Spiritual Warfare.”

Thigpen—a parishioner at St. Luke the Evangelist Church in Dahlonega—added, “If Christ knew what he was doing—as Christians must insist—and if the Gospel account is historically reliable—as Christians must also insist—then we must conclude that the forces described there as evil spirits are precisely that.”

I think O’Connor would love Thigpen’s book since he points out that demons can plant thoughts in our heads that make it more likely “we’ll be stirred to pride or anger or lust—or even despair.” Yes, we have free will so the devil can never force us to do anything, but he can certainly dangle temptations in our path.

Anyone who says demons aren’t real should peruse the headlines blaring atrocities such as political prisoners being beheaded, women being raped, and children being mistreated. As author Ronald Knox put it, “It is stupid of modern civilization to have given up believing in the Devil, when he is the only explanation of it.”

During Lent especially we might reflect on the voice that tries to lure us away from God. Maybe it’s the “everyone is doing it” mantra, which tries to justify watching pornography or having an affair. The voice might also lure us into feeding a deep-seated greed, which is like a ravenous monster that can never be sated.

In my younger years that voice was successful in getting me to stop going to Mass, and later to leave Catholicism behind. In many ways I was like Tarwater because I gave up believing in both Jesus and the devil at the same time without realizing who was behind my rebellion.

We won’t know for certain why the Marietta couple was murdered until the trial of the alleged perpetrator, but the likely motive was robbery. When I first read about this tragedy, I envisioned a demon whispering into someone’s ear: “No one will find out, and think of all the money you’ll have.”

This image called to mind an event that happened long ago when a man known to be a thief allowed Satan into his heart and went on to betray a friend—the kindest man who ever lived—for 30 pieces of silver.