Mr. Buckner suffered for his decision to come forward. He was ostracized by his colleagues. He received death threats. He was demoted from homicide detective to traffic cop. Though he was finally promoted to sergeant in 1995, his career was effectively over.

On Monday, the Louisiana State Senate unanimously passed a resolution honoring his decision to testify.

“Despite an awareness of what it would mean for him personally,” it read, “in one of the most pivotal moments of his life, he honored his oath as a law enforcement officer to uphold the Constitution and as a witness to testify honestly, and for his actions, he and his family paid a heavy price.”

Oris Benny Buckner III was born on July 16, 1951, in New Orleans. His parents, Oris Buckner Jr. and Marguerite (Bush) Buckner, had divergent experiences with the law — his father died in police custody when Oris III was young, while his mother was the first Black woman on the New Orleans police force.

He received a bachelor’s degree in criminal justice from Loyola University in New Orleans in 1978, and in 1991 he was ordained as a Baptist minister.

Along with his sister, he is survived by his wife, Stephanie Buckner; his son, Oris Buckner IV; his daughter, Amiya Lewis; his stepson, Ronnie Gilmore; his stepdaughters, Stephanie Powell and Tonette Vasquez; and several grandchildren. Another sister, the actress Carol Sutton, died in 2020. His daughter Angel Buckner died in 2010.

After he and his wife lost their home in 2005 during Hurricane Katrina, they moved to Houston. Mr. Buckner retired from the New Orleans Police Department and later taught criminal justice at Lee College, a community college in nearby Baytown, Texas.