On Wednesday, mystery deepened over the fate of Gen. Sergei Surovikin, the country’s former top commander in Ukraine, who has been dubbed “General Armageddon” for his ruthless tactics, and who has not been seen since the rebellion.

One of the country’s top lawmakers said, when pressed by a reporter, that the general was “taking a rest.”

“He is unavailable right now,” the lawmaker, Andrei Kartapolov, the head of the Russian Duma’s defense committee, added in a video posted on the Telegram messaging app before hurrying away from the reporter.

General Surovikin, was considered to be an ally of Yevgeny V. Prigozhin, the head of the Wagner mercenary company, whose forces mounted the brief insurrection in late June aimed at toppling Russia’s military leadership, before standing down in a deal with the Kremlin.

The New York Times reported that U.S. officials believe General Surovikin had advance knowledge of the mutiny but do not know whether he participated. In the hours after the rebellion began, the Russian authorities quickly released a video of the general calling on the Wagner fighters to stand down.

The lawmaker’s enigmatic comment about General Surovikin came two days after the Russian authorities released the first footage of the country’s top military officer, Gen. Valery V. Gerasimov, since the insurrection.

In the video, General Gerasimov was receiving a report from the Russian Aerospace Forces, which are run by General Surovikin. But the person giving the update in the footage was General Surovikin’s deputy, Col. Gen. Viktor Afzalov.

General Surovikin’s location is just one of the many mysteries that have arisen since the mutiny. Despite a deal announced by the Kremlin, under which Mr. Prigozhin would depart Russia for Belarus and avoid prosecution, the mercenary tycoon appears to have remained in Russia.

The Kremlin disclosed earlier this week that Mr. Prigozhin and his top commanders had met with President Vladimir V. Putin five days after the mutiny, raising many questions about what sort of deal had been struck with the former insurrectionists.

Russia, meanwhile, received another blow to its top military ranks. Lt. Gen. Oleg Tsokov, the deputy commander of Russia’s Southern Military District, was killed in Ukraine during Monday night missile strike on the occupied city of Berdiansk, marking one of the highest-level losses for Russia during the course of the war, Ukrainian authorities announced.

A Russian lawmaker and retired general, Andrei Gurulyov, confirmed Tsokov’s death in an appearance on state television Wednesday, saying he “died heroically.” The death recalled the early days of the war, when Ukrainian officials said they had killed approximately 12 generals on the front lines.

Russian authorities also arrested a Ukrainian man Wednesday on suspicion of gunning down a former Russian submarine commander, Lt. Gen. Stanislav Rzhitsky, earlier this week in the southern city of Krasnodar, where he had been serving as the deputy director of the city’s mobilization office.

Russian news outlets reported that General Rzhitsky, who posted his running routes publicly on the exercise service Strava, was shot to death while jogging in a Krasnodar park.

On Tuesday, the day after the body was found, Ukrainian military intelligence said on its official Telegram account that General Rzhitsky had commanded a submarine that was involved in missile attacks on Ukraine. Friends and relatives, however, told Russian news outlets that he had left the active-duty military service before the February 2022 invasion.

The state news agency RIA Novosti, citing an anonymous source in Russian law enforcement, reported that the man arrested Wednesday had admitted under questioning to being recruited by Ukrainian intelligence to carry out the killing.

General Rzhitsky’s name had been entered in the online database Myrotvorets, which posts photographs, social media accounts and telephone numbers of people considered to have committed crimes against Ukraine.

A red stamp was added over his photograph on the database reading, “Liquidated.”