Egyptian officials on Saturday disclosed that the word “fire” is clearly audible on the cockpit voice recording from EgyptAir Flight 804, but safety experts and a person involved in the investigation said there are no clear-cut answers so far about the sequence of events that brought down the jetliner almost two months ago.

Data downloaded from the Airbus A320’s black boxes, these people said, at this juncture haven’t provided conclusive information about where the fire started or why it apparently spread so quickly that it may have overwhelmed the crew and knocked out key electronic circuits, possibly affecting the black box recording devices themselves.

As a result, they said, barring some sudden breakthrough, investigators are preparing for a long slog to determine why the plane, cruising in the early morning hours over the Mediterranean Sea, crashed without a distress call from the cockpit, killing all 66 people on board.

According to these people, the probe is further complicated by tensions among the international team of investigators, which includes experts from Egypt, plane maker Airbus Group SE and France’s air-accident agency.

The Egyptian investigators leading the effort, they said, often appear reluctant to share details with Airbus and French crash experts partly due to fears that details prematurely may be disclosed or leak out to the media.

The upshot, according to these people, is that Airbus hasn’t had a central role in analyzing the cockpit-voice recording, and the company has relied largely on Egyptian authorities to alert it if some finding warrants sending emergency safety messages to other A320 operators.

No such messages have been issued. But by the same token, according to one person involved in the investigation, Airbus officials remain uncertain about where Egyptian investigators are focusing efforts to pin down the source of the fire.

Despite weeks of extensive analysis of data downloaded from the black boxes, supplemented by forensic examination of pieces of wreckage, some safety experts and investigators increasingly worry the recorders may have stopped working too soon to yield definitive answers.

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