ORLANDO, Fla. — Louis Omar Ocasio-Capo was 20, worked at a Starbucks in a Target store, and lived to dance. Stanley Almodovar III, a 23-year-old pharmacy technician, had posted a Snapchat video of himself singing and laughing on his way to the Pulse nightclub on Saturday. Eric Ivan Ortiz-Rivera, 36, nicknamed Shaki, had been married to his husband for about a year, worked at a Party City and a Sunglass Hut, and was entranced by interior design.

The dead were mostly young, mostly Latino and mostly gay — though some were none of those and a fair number were straight men and women enjoying an evening of Latin music. And on Monday, when their names were read aloud in the auditorium of a red-brick senior center, the worst fears of their families came true as the roster of the victims of the Orlando attack became horribly real.

Juan Ramon Guerrero was less than a month shy of his 23rd birthday and in his third year at the University of Central Florida in Orlando. He was quiet and kind, his uncle Robert Guerrero, 51, recalled. Like other members of his Dominican family, he liked Latin music, which is why he went to Pulse on Saturday night.

“He was not a party boy,” Mr. Guerrero said. The family found out that Juan had been hurt when someone saw him being carried out of the club and into an ambulance. Family members began a frantic search. Finally, a hospital confirmed the awful news. The bereft uncle, like so many other relatives, turned to Facebook to pour out his rage.