OSAKA (Kyodo) A Japan Coast Guard helicopter hit power lines and crashed Wednesday into the Inland Sea off Sanagi Island in Kagawa Prefecture, killing four of the five coast guardmen on board, police and JCG officials said, adding the fifth crewman remains missing.

The Bell 412EP, based at an air base of the 6th Regional Coast Guard Headquarters in Hiroshima Prefecture, was on a patrol when it crashed. It was not immediately clear why the helicopter hit the utility lines, but a witness said the chopper was flying low.

The identities of the four, whose bodies were retrieved from the sea by coast guard divers, were confirmed as pilot Masahito Fujimoto, 41, copilot Hitoshi Takahashi, 38, engineer Yasunobu Okamoto, 39, and communications officer Mitsuo Matsui, 55. Chief engineer Satoshi Odake, 56, remains missing.

The four men retrieved by coast guard divers were later confirmed dead.

A coast guard vessel found debris from the helicopter near the island, officials said.

"Immediately after a blackout took place, I heard a big bang," a 65-year-old woman who lives on the island said.

"Then I looked out and saw an orange helicopter floating on the sea, together with (several) helmets," she said.

A 67-year-old woman who saw the chopper also heard the crash. "I thought, 'wow, (it was flying) quite low,' " she said.

The helicopter left the base at around 1:45 p.m. for a patrol and was slated to return around 4 p.m. But at around 3:10 p.m., it hit a high-voltage power line about 100 meters high that connects Sanagishima and a smaller island nearby, Kagawa police said.