There were many side-eyes and questions when 28-year-old Chicago native Sandra Bland was arrested on a traffic violation in Texas in 2015, only to be later found hanging from a noose in her jail cell from an apparent suicide. Bland’s death and the circumstances of it sparked a national outcry and further sparked debates about police procedures and the mistreatment of black and brown people by law enforcement.

Say Her Name: The Life and Death of Sandra Bland, a new HBO documentary set to air at this year’s Tribeca Film Festival, seeks to answer the ongoing question, “What really happened to Sandra Bland?” Directed by Kate Davis and David Heilbroner, the documentary includes commentary from Sandra Bland’s family as they seek to unravel the circumstances behind her mysterious death.

Documentaries often leave viewers with more answers than questions, and Say Her Name looks like no exception. At its first peak, the documentary seemingly answers why Sandra Bland was in a jail cell by herself, and probes the missing video time stamps revolving around her arrest and incarceration. The documentary makes its world premiere at the Tribeca Film Festival on Wednesday, April 25, and later this year on HBO.

Watch a clip of Say Her Name: The Life and Death of Sandra Bland below.