The mother of Henry Nowak, the 18-year-old student fatally stabbed last December in Southampton, has spoken publicly for the first time about learning of her son’s death. Lucy Ross recounted the moment her daughter, Olivia, alerted her to police at the door, followed by officers informing her that Henry had been involved in an altercation and had died. “No words can explain that feeling,” Ross said.

Henry’s stepmother, Katie, described the family’s experience as having their world “changed twice”—first upon hearing of Henry’s death and again after viewing police footage of his arrest. The video, which drew widespread attention, showed officers handcuffing Henry despite his pleas that he had been stabbed. The footage raised questions about the immediate handling of the incident by law enforcement.

Henry had been wrongly accused of a racially motivated attack on Vickrum Digwa, 23, who was later sentenced to life imprisonment in June for Henry’s murder. The case sparked public debate over both the crime and the police response.

The family’s story and their ongoing campaign for justice are featured in an upcoming ITV documentary, Dear Henry: Our Fight For Justice, scheduled to air Thursday at 9 p.m.