A white woman writing an opera about the execution of a young African-American boy could easily become just another example of white artists profiting from black death. But Frances Pollock, who earned a master's degree in vocal performance from Peabody this year, managed to handle the subject respectfully and movingly in “Stinney,” the opera she composed about the true story of George Stinney, a 14-year-old African-American boy who was wrongly executed in 1944 for the murder of two young white girls. Pollock wrote her opera from the perspective of the two murder victims, to avoid issues of appropriation. And despite a less-than-ideal staging at 2640 Space that made it difficult to see a lot of the action, “Stinney” was a musically impressive, emotionally weighty work that thoughtfully confronted white people's dehumanization of and violence against African-American people. Of note: Members of Stinney's family attended the opening night of “Stinney,” and while admission to the opera was free, portions of donations went to the Innocence Project, a nonprofit that uses DNA testing to exonerate wrongly convicted prisoners.