The keyword phrase is a noun phrase functioning as an interrogative clause. The central point of inquiry is the verb "dies," which seeks the identification of subjects (nouns) whose fatalities are depicted in the film. The movie "Patriots Day" portrays the deaths of five key individuals: the three civilians killed by the initial bombings, a police officer murdered during the manhunt, and one of the perpetrators.
The film chronicles the deaths of the three victims of the Boston Marathon bombing on April 15, 2013: 8-year-old Martin Richard, 29-year-old Krystle Campbell, and 23-year-old Lingzi Lu. Their deaths are depicted in the immediate, chaotic aftermath of the explosions near the finish line. Later in the narrative, the film portrays the murder of MIT Police Officer Sean Collier, who was ambushed and shot by the Tsarnaev brothers on April 18. Finally, the death of perpetrator Tamerlan Tsarnaev is shown during the Watertown shootout; he is wounded by police and then run over by his escaping brother, Dzhokhar.
The film's portrayal of these deaths serves to ground the narrative in the factual tragedy of the event. The depiction is handled with a focus on the human cost and the gravity of the violence, rather than on gratuitous detail. These specific fatalities function as critical plot points, marking the transition from a city-wide tragedy to a focused criminal investigation and a violent manhunt, ultimately underscoring the stakes for both law enforcement and the community.