(CNN) Investigators with the National Transportation Safety Board are working on coming up with plans to recover the wreckage of a tour helicopter that crashed in Hawaii, killing seven people.

NTSB said. The helicopter crashed into a ridge on Thursday about 25 minutes after taking off from Lihue Airport, the agency said in a news release. It then fell about 100 feet and was engulfed in flames, theNTSB said.

On Monday, an NTSB investigator flew over the site to evaluate conditions and take photos of the wreckage's path, the agency said.

The site of the crash

"In the coming days the wreckage will be moved to a secure location where investigators will conduct a more thorough examination of the recovered evidence," it said.

The aircraft -- which was operated by Safari Helicopters, Inc. -- was equipped with an electronic locator, but officials did not receive a signal from it, Coast Guard Chief Petty Officer Sara Muir told CNN.

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