CAIRO — When an Egyptian student was arrested at the Cairo Airport recently, it was hardly an unusual event. Egypt’s security services routinely detain human rights defenders, lawyers, academics and other government critics, most of whom vanish into prison for years. Many complain of torture.

But the plight of this detainee, Patrick Zaki, 27, who works for a prominent Egyptian rights group, has received unusual international scrutiny thanks to an important difference: He was coming from Italy.

The University of Bologna, where Mr. Zaki was studying, took up his case, which became front-page news. Student demonstrations erupted in several cities, and Italian officials issued demands. The Italian mobilization was driven in large part by parallels with the case of Giulio Regeni, an Italian student who vanished in Cairo in January 2016 only to be found dead 10 days later, with signs of extensive torture.

Italians have been haunted by the fate of Mr. Regeni, 28, a doctoral candidate at the University of Cambridge. A public clamor for the truth about his death, which was widely blamed on Egyptian security agents, has become a national preoccupation. It has been heightened by frustration with Egyptian officials, whom Italian prosecutors accuse of covering up the killing.