MIAMI (AP) — U.S. officials have taken over the investigation of a Bahamas helicopter crash that killed billionaire coal magnate Chris Cline and six other people.

National Transportation Safety Board spokesman Eric Weiss confirmed Monday that the wreckage has been moved to a secure site in the United States. He says a preliminary report should be available in about two weeks. The full investigation could take up to two years.

The Bahamas Air Accident Investigation Department says flight and data recorders have been recovered and shipped to the NTSB in Washington for analysis.

Bahamian officials say cranes pulled the 15-passenger Augusta AW139 from the ocean over the weekend. Investigators remained onsite Monday documenting wreckage to determine the complete craft was recovered.

The helicopter crashed Thursday after taking off from a remote private island.