LONDON — A senior member of the Saudi royal family, who had feared returning to the kingdom, flew back to Riyadh from London on Tuesday in the most significant move in the royal family since the killing of the dissident Jamal Khashoggi.

[Update: Three senior members of the Saudi royal family are arrested.]

The return of Prince Ahmed bin Abdulaziz, which was confirmed by three Saudis close to him, comes amid an international backlash against the kingdom after the brutal death of Mr. Khashoggi.

Prince Ahmed, the younger brother of King Salman, had been afraid to return, associates of his family said, since he had made public comments last month that appeared to criticize Crown Prince Mohammed bin Salman, 33, the king’s favorite son and the de facto ruler of the kingdom.

As one of the most senior figures in the royal family, Prince Ahmed, in his 70s, could help bestow legitimacy on any family response to the furor over Mr. Khashoggi’s killing — whether that response might be some effort to limit the crown prince’s unrivaled power or instead to reinforce his grip on the kingdom.