Hawaii's health director died of an irregular heartbeat that was triggered when a small plane she was riding in lost power and crash-landed off the Hawaiian island of Molokai, police said Monday.

Loretta Fuddy's irregular heartbeat was the result of stress from the Dec. 11 crash, Maui police announced, revealing the findings of an autopsy conducted two days after the crash. The pilot and seven other passengers on the Makani Kai Air flight survived without major injuries.

Pilot Clyde Kawasaki and a passenger who swam to shore have said Fuddy appeared fine while bobbing in the water after everyone exited the plane and waited for help. Rescuers eventually pulled Kawasaki and the others from the water.

The National Transportation Safety Board's preliminary report on the crash said the single-engine plane floated for about 25 minutes before sinking.

Fuddy, 65, was healthy and didn't have any known heart problems, her brother, Lewis Fuddy, said Monday.

"She wasn't an anxious person," he said. "To be head of the Health Department, you have to have some cool nerves."

Fuddy gained attention in 2011 for her role in releasing President Barack Obama's Hawaii birth certificate to rebut claims he was born outside the U.S.

A spokeswoman said the Health Department had no comment on the cause of death.

Knowing the cause of Fuddy's death doesn't alleviate the grief, her brother said.

"I don't think it's every going to bring any comfort to us," he said. "We felt she had a lot of years to live and only the Lord knows why."

Kawasaki agreed that the cause of death doesn't make him feel better: "The end result is a fatality in a crash."

More questions remain, including why the engine lost power, he said.

One passenger, C. Phillip Hollstein Jr., has said he credits Kawasaki for being the reason nearly everyone survived.

When the plane's lone engine failed, the 60-year-old veteran pilot and passengers stayed calm as the aircraft glided toward the ocean and made a belly landing in rough waters, Hollstein recounted. The engine on the 2002 Cessna Grand Caravan turboprop cut out less than a minute after takeoff from the island of Molokai, just as the plane was making a turn toward its destination of Honolulu.

There was a "muffled bang," Hollstein has said, and "then we were a glider."

He said Kawasaki expertly maneuvered the plane after the engine failed, avoiding what could have been a catastrophic impact on the water. People put on life jackets and remained in the plane until it started sinking.

"There wasn't panic or anything," Hollstein has said. "It was very orderly."

Hollstein, 70, said he swam about a half-mile in 6-foot waves to Molokai's rugged shoreline, thinking the others aboard the plane were fine bobbing in their life vests, awaiting rescue. He said he was surprised to learn later that Fuddy died.

Fuddy was clinging to the hand of her deputy, Keith Yamamoto, who tried to help her relax, according to the Rev. Patrick Killilea, who consoled Yamamoto after the crash.

Fuddy and Yamamoto were on the flight after an annual visit to Kalaupapa, where the state exiled leprosy patients until 1969. The settlement is still run by the Health Department, though only a few former leprosy patients live there.

Makani Kai Air owner Richard Schuman said he has no idea why the engine failed. The plane had no previous problems, he said.

Kawasaki, who received stitches and was hospitalized after hitting his head on the control panel, said he's still waiting for medical clearances to be able to pilot a plane again. He said he flew in the co-pilot's seat last week for a trip to Molokai with one of the passengers from the crash. They met with some of the people who came to their aid during the aftermath.