In hindsight, it was almost inevitable.

A crowded city enjoying the friendly competition of world-class athletes amid a diverse, international crowd.

On Tax Day. In Boston.

In April, the month of lunatics. Waco and Oklahoma City on the 19th. Columbine. Virginia Tech.

Is there a pattern?

We’re almost a day from it now. The funerals are not all scheduled — or their number even fully known. The scorch marks still seem warm. The blood of innocent Americans, kids, still must be washed from the sidewalks.

An organized terror attack on American soil, choreographed for maximum media attention.

It hurts. The heart of New England is still reeling, and today will not be a normal day in Boston. Bags will be checked randomly. Streets will be closed. The city will bristle with police, and fear, as everyday freedoms are periodically revoked.

Even as we mourn and suffer with the victims, we praise and marvel at the heroism of first-responders and the everyday people who rushed into harm’s way.

Whether yesterday’s shabby bombing of the Boston Marathon was a homegrown or foreign brand of terrorism hardly matters to those whose lives were shattered, or to those whose sense of security was forced to relive September 11, 2001.

But the thugs responsible for this ugly attack must be caught. Based only on time, target and recent history, our deepest fear is we must start by looking within our own borders.