Authorities said Friday they had recovered remains of six of the seven people on board a tour helicopter that crashed along one of the most rugged and remote coastlines in Hawaii. Officials confirmed on Saturday that there were no survivors.

Kauai Fire Department Battalion Chief Sol Kanoho said at a press conference Friday that there were "no indications of survivors." Despite not finding the remains of a seventh victim in a search on Saturday, the Kaua'i Police Department declared all the passegners dead, "Due to the additional recovery efforts, the nature of the crash and impact damage."

The helicopter had failed to return Thursday from an excursion over a mountainous area on the island of Kauai. Authorities wouldn't comment on the conditions of the crash until the National Transportation Safety Board arrives to investigate. The NTSB said they are sending three investigators.

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Kauai authorities returned to the site of the wreckage ― in a remote area of Kokee ― on Saturday to search for the seventh set of remains. The remains were not found, and search operations were suspended and the investigation was handed over to the National Transportation Safety Board.

The helicopter was carrying a pilot and six passengers, including two children, CBS Honolulu affiliate KGMB-TV reports. The chopper didn't come back from a tour off the Na Pali coast of the Hawaiian island of Kauai.

"First and foremost, our thoughts and prayers are with the families of these passengers," said Kauai Mayor Derek S.K. Kawakami in a news release. "Operations continue and we are doing everything we can at this time."

Petty Officer 1st Class Robert Cox, of Coast Guard Joint Rescue Command Center Honolulu, called weather conditions in the search area "challenging," with low visibility and blustery winds.

Part of the Na Pali coast of the Hawaiian island of Kauai that a helicopter was touring on December 26, 2019. KGMB-TV

"We have trained crews responding and on scene searching for any signs of the helicopter and those aboard," Cox said in a news release issued Thursday night.

The Coast Guard was alerted to the missing Kauai-based helicopter at about 6 p.m. local time Thursday, some 40 minutes after it was supposed to return.

The aircraft is equipped with an electronic locator, but no signals have been received, officials said.

The Coast Guard said it launched an MH-65 Dolphin helicopter, a cutter and other resources to search for the missing helicopter.