MOSCOW, Aug 24 (Reuters) - Crash investigators on Thursday picked through the wreckage of a jet said to have been carrying Russian mercenary chief Yevgeny Prigozhin that crashed with no survivors, two months after he led a mutiny against the army leadership.

Two U.S. officials told Reuters Washington believed a surface-to-air missile originating from inside Russia likely shot down the plane, though they said the information was preliminary and under review. They spoke on condition of anonymity and offered no evidence.

Russian investigators opened a criminal probe but there has been no official word from Moscow on what may have caused Wednesday evening’s crash, or even official confirmation of Prigozhin’s death beyond a statement from the aviation authority saying he was on board.

The Kremlin and the Defence Ministry have made no comment on the fate of Prigozhin, 62, head of the Wagner mercenary group and a self-declared enemy of the army top brass over what he said was its incompetent prosecution of Russia’s war in Ukraine.

President Vladimir Putin made a virtual statement to a summit of the BRICS nations in South Africa which his foreign minister, Sergei Lavrov, was attending. Neither referenced the plane crash in which 10 people were said to have been killed.

State media gave the disaster low-key coverage.

The Embraer Legacy 600 (EMBR3.SA) executive jet, which had been flying from Moscow to St. Petersburg and was reported to have also been carrying senior members of Prigozhin’s team, crashed near the village of Kuzhenkino in the Tver region north of Moscow.

A Reuters reporter at the crash site on Thursday morning saw men carrying away black body bags on stretchers. Part of the plane’s tail and other fragments lay on the ground near a wooded area where forensic investigators had erected a tent.

The Baza news outlet, which has good sources among law enforcement agencies, reported that investigators were focusing on a theory that one or two bombs may have been planted on board.

Unnamed sources told Russian media they believed the plane had been shot down by one or more surface-to-air missiles. Reuters could not confirm either account.

Residents of Kuzhenkino said they had heard a bang and then saw the jet plummet to the ground. The plane showed no sign of a problem until a precipitous drop in its final 30 seconds, according to flight-tracking data.

One villager, who gave his name as Anatoly, said: “It wasn’t thunder, it was a metallic bang - let’s put it that way.”

Mourners left flowers and lit candles near Wagner’s offices in St. Petersburg.

‘MASTER OF ILLUSIONS’

“The first thing I believe is that this man committed the most serious crimes possible for a military man to commit,” a woman who gave her name only as Yelena told Reuters on the streets of Moscow. “I think his safety was only guaranteed in exchange for him stopping what he started. But he didn’t stop.”

A man who only gave his name as Boris said: “This man was, in fact, a master of illusions. Maybe he didn’t die. No one knows yet. They won’t show the funeral or the body.”

A Telegram channel linked to Wagner, Grey Zone, pronounced Prigozhin dead on Wednesday evening, hailing him as a hero and a patriot who had died at the hands of “traitors”.

Amid the absence of verified facts, some of his supporters have pointed the finger of blame at the state, others at Ukraine, which marked its Independence Day on Thursday.

Whoever or whatever was behind the crash, his death would rid Putin of someone who had mounted the most serious challenge to his authority since he came to power in 1999.

It would also leave Wagner, which incurred Putin’s wrath in June by staging a failed mutiny against the army top brass, leaderless and raise questions about its future operations in Africa and elsewhere.

Rosaviatsia, Russia’s aviation agency, published the names of all 10 people on board the plane, including Prigozhin and that of Dmitry Utkin, his right-hand man.

Abbas Gallyamov, a former Putin speech writer turned critic, suggested without offering evidence that the Russian leader was behind the crash.

“The establishment is now convinced that it will not be possible to oppose Putin,” Gallyamov wrote on Telegram. “Putin is strong enough and capable of revenge.”

U.S. President Joe Biden told reporters he did not know what had happened.

“But I’m not surprised,” Biden said on Wednesday. “There is not much that happens in Russia that Putin is not behind.”

Flightradar24 online tracker showed that the plane had dropped off the radar at 6:11 p.m. (1511 GMT). An unverified video clip on social media showed a plane resembling a private jet falling out of the sky.

Prigozhin spearheaded the mutiny against the army leadership on June 23-24 which Putin said could have tipped Russia into civil war. He also spent months criticising Russia’s war in Ukraine - which Moscow calls a “special military operation” - and had tried to topple Defence Minister Sergei Shoigu and Valery Gerasimov, chief of the General Staff.

The mutiny was ended by an apparent Kremlin deal which saw Prigozhin agree to relocate to neighbouring Belarus. But he had appeared to move freely inside Russia.

Prigozhin posted a video address on Monday which he suggested was made in Africa. He turned up at a Russia-Africa summit in St. Petersburg in July.