N.Y. Times correspondent Peter Baker, reporting from Munich: “Just hours after her husband was reported dead, Yulia Navalnaya made a dramatic, surprise appearance at a gathering of world leaders in Munich on Friday. Taking the stage, she denounced President Vladimir V. Putin of Russia and vowed that he and his circle “will be brought to justice.”

“The diplomats and political leaders at the Munich Security Conference were already reeling from reports that her husband, Aleksei A. Navalny, the Russian dissident, had died in prison under suspicious circumstances when Ms. Navalny stunned the hall by striding in. Conference organizers quickly wrapped up a session with Vice President Kamala Harris and turned the microphone over to Ms. Navalnaya.

“’We cannot believe Putin and his government,’ Ms. Navalnaya told the audience. ‘They are lying constantly. But if it’s true, I would like Putin and all his staff, everybody around him, his government, his friends, I want them to know that they will be punished for what they have done with our country, with my family and with my husband. They will be brought to justice, and this day will come soon.”

“Ms. Navalnaya spoke clearly and calmly, with remarkable composure, her face etched with evident pain but under complete control. Standing at the lectern, she clasped her hands in front of her and stared straight ahead as if willing herself to focus on her message.

“The audience was captivated and gave her an emotional standing ovation when she finished.”