Investigators have questioned one of Russia’s top generals about the failed mutiny that presented the greatest challenge to Russian President Vladimir Putin’s quarter-century rule.

Sergei Surovikin was quizzed by officials representing military prosecutors over several days about his links to Wagner mercenary leader Yevgeny Prigozhin, according to a person with knowledge of the matter, who asked not to be identified because the information is sensitive.

The general is being kept in one place but isn’t in prison, and investigators are treating him cautiously to avoid antagonizing others within the military who admire Surovikin’s record of achievements with the army, the person said.