Twenty-seven is the official count of victims: 20 innocent children … six adults connected with their school … the mother of the gunman who murdered them and her.

The unofficial toll a gunman’s rampage on Friday in Newtown, Conn., may be incalculable: the parents of the children at Sandy Hook Elemetary School; the children’s siblings; the surviving schoolchildren who never will totally forget what they heard and saw that morning. There’s no way to predict how many of them will have their lives irreversibly traumatized by our latest American horror story.

But, as we count the victims, perhaps we need to add one more.

Peter Lanza had just pulled his blue Mini Cooper into the driveway of his home in Stamford, Conn., last Friday afternoon when a reporter from the local newspaper approached him. His son, the reporter informed him, was believed to have murdered some children at Sandy Hook Elementary School a few hours earlier.

It’s almost impossible to imagine what Peter Lanza felt — what any parent would feel — at that moment. But in a statement he released the next day he declared, “We too are asking why?”

Like so many other questions, there may never be a satisfactory answer. For the sins of his son, Peter Lanza most likely will be condemned to a lifetime of guilt, whether deserved or undeserved. A lifetime of questions.

What had he done, as a father, that might have lead to his younger son’s actions? What hadn’t he done? Was he too strict? Too lenient? Had he been too buy pursuing his career as a successful tax executive to notice the danger signs? Did the divorce from Adam’s mother play a part?

Peter Lanza is not the first father who will be spending the rest of his life asking himself questions like those.

John Hinckley Sr. had to ask them every day after his son attempted to assassinate the president of the United States. William McVeigh had to be tormented by them, wondering what he might have done to prevent his son from causing the Oklahoma City bombing that claimed 168 victims, 19 of them children under the age of 6.

Not everyone is willing to absolve Peter Lanza of guilt. As one online post demanded, “Does he KNOW his son at all?”

But that’s a question virtually any parent can ask himself or herself. Because, no matter how hard we try, there are no guarantees in parenthood. And while we may not accept credit for their achievements, we always will feel guilt for their failings.

Whether Peter Lanza was a good father, a bad father or an indifferent father may never be answered. But this much is certain: He, too, lost a son.

He, too, is a victim.