WASHINGTON — I’ve written variations of this column a couple of times during the past 20 years, but certain occasions bear revisiting — and surely the disappearance of a friend is one.

Dail Dinwiddie was my son’s baby sitter/nanny when she vanished on Sept. 24, 1992. He was 8 and she was 23. He’s now five years older than she was then — and Dail would be 43. Police in Columbia, S.C., where she disappeared, recently released an updated photograph showing how they imagine Dail would look today (http://ow.ly/dYXev), based in part on how her parents and brother have aged.

The doctored photo shows an attractive middle-aged woman. Back then, Dail was a doll — just 5 feet tall and not quite 100 pounds, a blithe spirit full of laughter. I could have tucked her under an arm without much strain. Apparently, someone else did.

She was like any other girl that night — a U2 concert-goer with a pack of friends who migrated afterward to a section of town, Five Points, where college students often congregate into the early morning hours. Just a few blocks from the University of South Carolina, Five Points is a friendly commercial intersection of restaurants, bars and boutiques. It is always daytime there, with nearly as much foot traffic at 2 a.m. as at 2 p.m.

Dail was last seen around 1:30 a.m. by a bouncer at one of the popular watering holes, Jungle Jim’s. She had become separated from her friends and asked the bouncer if he’d seen them. He remembered watching Dail walk down the sidewalk toward another bar in the next block.

The next afternoon, Dail’s mother called me to say Dail hadn’t come home the night before and that I should meet my son at the bus stop. Hanging up, I wept. I knew Dail well enough to know that she would not just fail to come home without notifying her parents. She was too considerate for that. She certainly would never let her 8-year-old charge be left alone on a street corner. Something had happened to her.

One does what one can in such situations, but what? Police don’t usually begin looking for an adult for at least 24 hours because, statistically, most adults who disappear in this country leave of their own volition. But 24 hours is a long time, after which most clues are cold and the chances of finding someone greatly reduced.

At the time, I had a work space in Bud Ferillo’s public relations office. Upon hearing what had happened, Bud offered his entire office — telephones and staff — to help organize a search effort. Ferillo is better known today as the documentary filmmaker who brought national attention to the dismal condition of South Carolina public schools with “Corridor of Shame.”

Within a matter of days, we had hundreds of volunteers, mostly students, and thousands of fliers with Dail’s picture posted around South Carolina and, thanks to volunteer truckers, distributed in every state in the country. Her parents, Jean and Dan, appeared on a couple of talk shows. Dail’s friends re-enacted the night of her disappearance, hoping some useful clue would surface. Psychics dreamed of wooded lots, vacant houses and riverbeds.

Amid the flurry of well-meaning folks, some members of the community complained that “they” only mobilize when white girls disappear. I’ve never been sure who the “they” are. I’ve only had one friend disappear and I did what little I personally could. Even so, I realized that the observation was not without merit. What does happen to other adults who vanish, I wondered?

This question led to the establishment of a nonprofit organization, the Dail Dinwiddie Safe Streets Foundation, dedicated to helping police and families find the missing, as well as educating young people about the buddy system. Our efforts never resulted in a happy ending — some of the missing were found dead, others in jail — but at least families had a means to channel their horror in constructive ways. Just getting a missing family member’s picture in the newspaper was better than nothing.

Eventually, the organization named for Dail dissolved. Board members died; volunteers grew up, got jobs and married. People moved on and the safe streets foundation became a stack of boxes in a corner of my office.

Twenty years fly by when you’re not looking for a missing child. The Dinwiddies are still looking for theirs. Someone reading this knows someone who knows something that could bring peace to the Dinwiddies.

Perhaps, even you?

Kathleen Parker is a Washington Post columnist. Her email address is kathleenparker@washpost.com.