In a major development in the investigation of the boat fire that killed 34 people off the coast of Santa Cruz Island, authorities now believe all crew members were asleep when the blaze broke out aboard the Conception, according to a preliminary report by the National Transportation Safety Board released Thursday.

Five crew members were sleeping in berths behind the wheelhouse. Another was asleep in the bunk room where the others victims were sleeping.

Only five crew members managed to escape. 

While the cause of the fire remains undetermined, the Los Angeles Times has reported that investigators found serious safety flaws aboard the vessel.

L.A. Times crime reporter Richard Winton wrote the incident is being treated as a criminal investigation.

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