NEW YORK -- Regardless of what cause is finally pinpointed, EgyptAir Flight 990 already has earned a place in aviation history with one of the most bizarre ends to a seemingly routine flight.

An apparent prayer uttered just before the plane's fatal plunge from 33,000 feet is being closely scrutinized by the National Transportation Safety Board, the FBI and the Egyptian government. The tape from the cockpit voice recorder is receiving nearly the same intense study once given to the film of the assassination of President John F. Kennedy.The central question: Why would a wide-bodied jet with 217 people aboard suddenly crash into the ocean when nothing appeared mechanically wrong and no distress call was made?

One theory is that the substitute co-pilot, Gameel El-Batouty, deliberately crashed the Cairo-bound plane Oct. 31. That account is being questioned by Egypt.

A statement made by a crew member in the co-pilot's seat -- presumed to be El-Batouty -- just before the autopilot was turned off and the fatal dive began originally was quoted by a source as: "I made my decision now. I put my faith in God's hands."

But government officials now say the first part of the phrase about making a decision was not on the tape. Egyptians say the second phrase is commonly used by Arabs.

Still, one source who spoke to The Associated Press on condition of anonymity, said the El-Batouty scenario "is not hung on the prayer." He wouldn't provide details.

Officials are cautious in discussing the investigation over sensitivity to Egypt.

NTSB Chairman James Hall said that as investigators looked at evidence, they "began to feel that the crash might, and I emphasize 'might,' be the result of a deliberate act."

But Hall's agency has delayed turning the probe over to the FBI as a criminal case because of Egyptian objections.

On the "Today" show this morning, Hall was asked whether anything more was found over the weekend.

"At this point in time the board has not found any information to believe that this is a mechanical or weather-related event that occurred," he said. "But our investigation is far from complete."

Despite the official delay, Lewis Schiliro, an FBI assistant director heading that agency's probe, said the FBI is "not in a holding pattern."

The agency has quietly but vigorously been investigating the crash, dispatching 250 agents, interviewing everyone who touched the plane in the days before it went down and studying the backgrounds of everyone aboard.

Eventually, agents will have to do similar work in Cairo, but they will need Egyptian approval first.

Agents scrutinizing crew members' backgrounds plan to do voice-stress tests on the cockpit recordings. They also want to know what benefits were left to families of those who died in the line of duty, and they want to review bank statements, insurance policies and phone records.

"Most of the work being done by the FBI is time-sensitive work, work that cannot wait for the NTSB to make a determination," said Jim Davis, an FBI spokesman.

If the case is determined to be criminal and there is no link to a terrorist group or anyone outside the plane, the FBI investigation could be completed in a couple of months.

So far, this picture of the crash has emerged from the voices and data recorded in the cockpit and radar:

The Boeing 767 rose routinely after takeoff from New York's Kennedy Airport. It had reached its cruising altitude for the 11-hour flight when the 57-year-old pilot, Ahmed al-Habashi, apparently left the cockpit briefly.

This appeared to have left the plane in the hands of El-Batouty, 59, the relief co-pilot who shortly before had come into the cockpit announcing he wanted to fly earlier than scheduled.

After the captain left, El-Batouty apparently made the remark about his fate being in God's hands. Then the autopilot was disengaged. It was 1:49:46 a.m.

Eight seconds later, the plane was in a steep dive at near supersonic speed.

Investigators say the pilot could be heard on the cockpit recorder saying, "What's going on?" and apparently grabbed the steering yoke to try and bring the plane out of its descent.

"Pull with me! Please. Pull with me!" investigators quoted him as saying.

The plea was met with silence from El-Batouty, the recorder showed. Flight data indicates that while the pilot pulled up, the co-pilot apparently pushed down to point the nose toward the ocean.

The plane went to 16,000 feet and both of the engines were shut off. It then swooped up 8,000 feet before it then plummeted into the ocean about 60 miles south of Nantucket Island, Mass.

Schiliro, of the FBI, said the probe has purposefully mirrored the steps taken by the FBI in the TWA Flight 800 disaster off New York's Long Island. After months of suspecting terrorism in the 1996 explosion that killed 230 people, officials agreed mechanical failure was to blame.

In the EgyptAir crash, if it is determined that someone in the cockpit was responsible, investigators must determine whether he acted alone and whether terrorists were behind it. So far, investigators say, nothing points to terrorism.