One of the four police officers who shot and killed Amadou Diallo is set to receive a promotion Thursday by the New York Police Department. Kenneth Boss killed the unarmed 22-year-old as he reached for his wallet inside while being questioned at his Bronx apartment in 1999, triggering widespread protests against police brutality. Boss, who fired five of the 41 shots that hit Diallo, will be promoted to sergeant. Diallo’s mother, Kadiatou, expressed both sadness and frustration to the New York Daily News at the news of the promotion. “You have so many police officers out there who deserve to be promoted, and this man is being promoted?” she asked. Boss and three others were acquitted of murder charges in the West African immigrant’s death.