Where is the evidence?

That continues to be the essential question at the heart of the controversy over what brought down the Russian Airbus 321 over the Sinai on Oct. 31, killing all 224 people aboard.

More than two months later we are no closer to an answer to what happened, even after the Egyptians released what they’re overselling as a “preliminary report” Monday.

Preliminary reports are customarily delivered by investigators in a country in which a crash occurs, sometimes within weeks, more often within a few months—but rarely, if ever, with such scant factual information as the one released in Cairo, signed off by Ayman El-Mokaddem, the chief of the Egyptian investigation.

Without any forensic documentation at all, the Egyptians say that they have no evidence that the jet was brought down by a bomb.

In fact, this investigation is turning out to be one of the worst cases in the entire history of air crash investigations in which competing interests produce different versions of the same event:

Russia remains adamant that the airplane was brought down by a bomb. A Kremlin spokesman, reacting to the Egyptian report, said, “I can remind you of the conclusion reached by our experts and special forces…that it was a terrorist act.”

Western powers have been slightly more cautious. British Prime Minister David Cameron says it was “more than likely” an act of terrorism; U.S. intelligence officials, while making no explicit public statement, have widely briefed members of Congress, civilian security experts and reporters that they are “99 percent” confident that a bomb was planted on the airplane—though they are not prepared to say by whom or to offer any actual evidence.

ISIS, more than two weeks after the crash, released a picture of a bomb in the form of a can of soda packed with explosive attached to a timer and detonator, but—suspiciously—did not explain how such an attack had been successfully carried out.

However, neither the Egyptian report nor any of the assertions that it was a bomb meet the most basic evidential standards required of an accident investigation.

This is all the more frustrating because every piece of the wreckage was openly visible and accessible to investigators. It ranged in condition from large sections of the airplane incinerated by fire to other, less damaged pieces scattered over a wide area.

Investigators have a long experience of finding evidence of a bombing under far more challenging conditions than these. For example, in 1985 an Air India Boeing 747 flying from Montreal to London was brought down by a suitcase bomb over the Atlantic, killing 329 people.

Although the main part of the 747 lay on the seabed at a depth of 6,700 feet it was quickly located and the black boxes recovered. Evidence from those and from many of the 132 bodies that were recovered showed that the jet had broken up in the air after an explosion in the cargo hold.

Nobody disputes that the Russian jet was suddenly torn apart in the sky. That could have happened only as a result of either a catastrophic structural failure or a bomb placed either in the cabin or in the cargo hold.

One event in the history of the Airbus could have a bearing on a structural failure. In 2001, when it was owned by Middle East Airlines, it suffered a heavy landing at Cairo—a tailstrike in which the tail hit the runway before the wheels and required extensive repairs. Tailstrikes have led to fatal crashes in the past when repairs were inadequate or flawed.

Investigators from France (where the Airbus was built), Ireland (where the jet was registered), and Russia are involved in the investigation but it is the Egyptians who appear to be controlling how much hard evidence has—or has not—been gathered and how much of it is being released.

Somewhat pointlessly, El-Mokaddem said that the investigation committee had visited the debris field 15 times and that the Egyptian air force was moving key pieces of wreckage to Cairo for more intensive examination.

And El-Mokaddem doubled down on the claim that there was no evidence of terrorism by telling a TV interviewer that neither was there any evidence that terrorists had “infiltrated” the airport at Sharm el-Sheikh, the flight’s departure point.

The Egyptians could be suffering the unhappy fate of all regimes like theirs that have little credibility: Few people will believe them even if they are telling the truth.