On a recent day in the top-floor gallery of the Guggenheim Museum, Chaédria LaBouvier, a 34-year-old independent curator and the first black woman to organize a solo exhibition at the Guggenheim, contemplated the small, ostensibly minor painting by Jean-Michel Basquiat that drove her to years of fervent research.

In the Basquiat canon, it was “a not very good scrap of painting,” The New Yorker critic Peter Schjeldahl recently wrote. It was almost not a discrete work of art at all. Mr. Basquiat painted it directly onto Keith Haring’s studio wall ; it would have been lost had Mr. Haring not cut it out and set it like a masterpiece in the ornate frame it still inhabits. (It was over Mr. Haring’s bed at the time of his death.)

But “Defacement (The Death of Michael Stewart)” is also, as far as Ms. LaBouvier or anyone else has determined, the only work in Mr. Basquiat’s vast oeuvre that addresses a current event of his time — a gruesome tragedy that took the life of a young black artist and shook the Lower East Side art community.

“This was a form of evidence, in a sense,” Ms. LaBouvier said.

Her show, “Basquiat’s ‘Defacement’: The Untold Story,” centers on this piece as it develops a picture of the death of the 25-year-old man grievously injured in transit police custody and its effect on other artists. The exhibition argues for a fresh look at the impact of the racial tension of the 1980s on Basquiat and his peers. In so doing it uncovers new material, including several works that important artists made in response to the incident that have never been shown before. And it presents, for the first time, some of the artwork that Mr. Stewart himself had been making.