WASHINGTON — Quick, before you forget:

Before Thursday, what did you think you knew about the sniper who terrorized metropolitan Washington?

Already, in a too-tiny-to-measure way, we’ve forgotten. Each bit of information we’ve absorbed has slightly shifted the inner map that directs and shapes our perspective.

Now that we’ve seen the apparent culprits — their genders and ages and the bright breadths of their snapshot smiles — we’re rearranging the mental furniture.

We’re beginning, inevitably, to forget.

Some things, however, I’ll remember. Like the recent taxi ride from my home during which the driver — a mahogany-skinned Kenyan — announced:

"This sniper is no black man. The police are looking for a crazy white man. Someone like the Unabomber. …

"Serial killings?" he continued. "Black people don’t do that."

Even when I mentioned people of color who’d committed multiple murders, the cabdriver shook his head.

The killer, he knew, couldn’t be black.

Well, for weeks after Sept. 11, I thought I knew how horrible it feels to be a potential terrorist victim. I thought I knew how precious my sons are to me.

Now I know this:

I knew nothing.

Why? Because even Sept. 11 didn’t make me pray as passionately or hold my children as closely as did the shootings. Because merely walking from my car into Home Depot — with my heart pounding so audibly, it seemed to have relocated to between my ears — taught me new lessons about terror’s effects.

Because despite my assertions to the contrary, part of me agreed with that cabdriver.

As thrilled as I am that suspects have been caught, I’m surprised by their blackness. Ted Kaczynski, John Wayne Gacy, Ted Bundy and others helped me to feel as culturally distanced from those who commit serial murders as I’ve felt personally outraged by "brothers" who’ve shot innocents during drug drive-bys.

I "knew" that an African American sniper wouldn’t choose to rip open a black child’s midsection. A black sniper wouldn’t make six of his 13 victims people of color — four of them black males.

I’d always enjoyed the easy warmth shared by many African Americans, the thoughtless "How ya doin’?" that’s often tossed — even to strangers — among us. I felt secure in my assumption that no one who’d weathered racism and shared our long-devalued cultural experience would do this. How naive.

But spending centuries being harshly judged as a group knit African Americans together. Sometimes, that kinship makes us think we know what we would — and wouldn’t — do.

So we forget the obvious: Human beings are capable of anything.

So what should we "know" now?

That it’s high time black folks became as adept as white people at accepting that those who look like them do unspeakable things. These individuals’ actions don’t "reflect badly" on us as a group.

They reflect badly on us all as human beings.

In a multiple-homicide case in which African Americans figured prominently among victims, police, journalists, academics and even FBI profilers, the possibility that the perpetrators are black isn’t our personal shame. If the secretary of state and the most recent "Survivor" can be black, so can a madman.

The fact that, when the inevitable movie is made, the suspects could be played by Denzel Washington and Lil Bow Wow rather than Billy Bob Thornton and Josh Hartnett doesn’t change one indisputable all-American fact:

The sniper could have been anybody.

Most Washingtonians, of every shade, understand that. So what did we learn that we mustn’t let slip away?

The existence of so many good people — as exemplified by the victims, each exemplary in his or her own way. And this:

Before a stroll with my child felt like a gantlet run, I would have sworn I was empathetic. I knew — for a fact — that the fear felt by people threatened by war and terror anywhere resonated with me.

But feeling literally under the gun, being wary and weary in new, horrible ways made real for me what I’d only sensed:

No one should feel as frightened as we’ve felt the past three weeks.

No one.

Not one mother or father or son or auntie. Not one child. Not one Palestinian or Israeli or Rwandan or Russian or Colombian.

Certainly not the mothers, fathers and grandparents in poorer sections of Washington — people who live just a few miles from the sniper’s suburban haunts — who have for years worried about their children coming home in one piece.

From a distance in "safe" Montgomery County, I’ve cared deeply for those people. But now I know:

No one should feel that. We should do everything in our power to prevent anyone from feeling it.

Before we forget.

Donna Britt can be reached at The Washington Post Writers Group, 1150 15th St. NW, Washington, DC 20071-9200.