Story highlights The two ships collided on the Fitzgerald's starboard side directly next to the berthing area

The US Navy, the US Coast Guard and Japanese naval and maritime authorities are all conducting investigations

Washington (CNN) Five of the seven Navy sailors who died aboard the guided-missile destroyer USS Fitzgerald when it collided with a cargo ship off the east coast of Japan may have been almost instantly "incapacitated" and died quickly, according to a preliminary Navy analysis, a defense official told CNN.

That assessment is based on an examination of the point of impact and the berths in which the sailors were likely sleeping.

The two ships collided on the Fitzgerald's starboard side directly next to the berthing area, where sailors sleep. The impact ripped the Fitzgerald open and caused water to pour in.

The official also noted the Navy is trying to corroborate accounts which suggest that the two sailors who weren't almost instantly "incapacitated" attempted to help the other five escape the incoming water.

"But at some point the ship somehow lost communication," with the two sailors and they also perished, according to the official. All seven were found dead in the flooded area.

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