Ever Orozco’s afternoon on Monday began with a short car trip across Queens to take his wife to a doctor’s appointment. For Mr. Orozco, 69, of Woodside, it was a routine task on a crisp and sunny day.

But minutes after dropping her off, the police said, Mr. Orozco encountered a 22-year-old man who pulled out a knife and stabbed him to death.

What at first appeared to be a frightening daytime street crime grew stranger on Tuesday. It was not a robbery or a dispute between acquaintances, the police said, but a random and hate-fueled assault prompted by the younger man’s stated belief that Mr. Orozco had made sexual advances.

The suspect, Steven Torres, told detectives after his arrest on Monday that Mr. Orozco had been “blowing kisses” at him and made a sexual gesture as the two crossed paths at 90th Street and Roosevelt Avenue in Jackson Heights.