WHIDBEY ISLAND, Wash. >>

A civil rights activist, a business owner, a lawyer, an engineer and the founder of a winery and his family were on the floatplane that crashed in the waters of Washington state’s Puget Sound, killing 10.

The U.S. Coast Guard released the names of the victims early Tuesday. The body of one of the dead was recovered after Sunday afternoon’s crash, but the other nine remain missing despite an extensive search.

The Northwest Seaplanes flight was on its way from Friday Harbor, a popular tourist destination in the San Juan Islands, to a Seattle suburb when it went down without sending out a distress call. The cause of the crash was not immediately known, but the Federal Aviation Administration earlier this year issued a safety directive for the type of aircraft involved.

A team from the National Transportation Safety Board is investigating the crash of the DHC-3 Otter. At a Tuesday evening news briefing, Tom Chapman from the NTSB said investigators on scene wouldn’t speculate on a cause of the crash and crews were collecting information about the approximately 35-minute flight.

Chapman said the agency is directing the search for the wreckage and sonar equipment was being used.

The dead include pilot Jason Winters, activist Sandy Williams, winemaker Ross Andrew Mickel, his pregnant wife Lauren Hilty and their child Remy Mickel. Also killed were passengers Joanne Mera, Patricia Hicks, Luke Ludwig, Rebecca Ludwig and Gabrielle Hanna. The Coast Guard did not provide hometowns.

Williams, from Spokane, Washington, was a lecturer, filmmaker, founder of the Carl Maxey Center and editor of The Black Lens, an African American-focused newspaper.

“Sandy was a voice for the voiceless, a tireless advocate for marginalized people in Spokane, a journalist unafraid to speak truth to power, a builder of hope in her vision for the Carl Maxey Center, and a beloved friend to countless members of our community,” The Spokane County Human Rights Task Force said on Facebook.

Thayne McCulloh, president of Gonzaga University, said the community lost a leader, teacher, activist and powerful voice.

Also from Spokane, Hicks was a retired teacher.

Mickel was the founder of the Ross Andrew Winery in Woodinville, Washington.

“We are deeply saddened and beyond devastated at the loss of our beloved Ross Mickel, Lauren Hilty, Remy and their unborn baby boy, Luca,” the Mickel and Hilty families said in a statement. “Our collective grief is unimaginable. They were a bright and shining light in the lives of everyone who knew them.”

The Washington State Wine Commission said in an email that Ross had “an incredible impact on the Washington wine community” and will be greatly missed.

Mera was a business owner from San Diego, The Seattle Times reported. Her niece, Sami Sullivan, said she was visiting family in Seattle. She leaves behind three children and a husband of more than 30 years, Sullivan said.

“Joanne Mera was someone everyone gravitated towards,” Sullivan said in a statement. “She was the life of any party and the soul of our family.”

The Ludwigs, a couple from Minnesota, also perished in the crash. Luke Ludwig was an engineering leader with Arizona-based HomeLight Home Loans.

“The entire HomeLight team extends our deepest sympathies to both Luke and Becca’s families, friends, and loved ones,” the company said in an email. “Luke was a deeply devoted father, husband, outdoorsman, and coach for his kids’ sports teams, known for his remarkable kindness and generous spirit.”

Seattle lawyer Gabby Hanna was returning from a friend’s wedding when the plane went down, The Seattle Times reported.

“She was a fierce, fierce young woman, in the best of ways,” her father, Dave von Beck, said. “There are no words to describe the pain.”

The Coast Guard ended the search for survivors Monday afternoon. The plane went down in Mutiny Bay off Whidbey Island, about halfway between Friday Harbor and its destination in Renton.

The owner of the seaplane company was aboard one of two flights that took off on Sunday, Scott Giard, director of the U.S. Coast Guard’s search and rescue for the Pacific Northwest, said at a news conference.

The owner told authorities he saw the other plane divert slightly off course and he tried to make radio contact but was unable to.

“Shortly after that, he noticed on his flight tracker that the flight had stopped tracking and notified authorities,” Giard said.

Officials received reports that “the aircraft dropped suddenly at a fair amount of speed and hit the water,” Giard said.

There was no distress call or distress beacon from the crashing plane, he said. The aircraft has an electronic locating transmitter onboard, but they have not received any transmission.

Steven Wallace, former director of FAA Office Accident Investigations, said the NTSB will look at all other accidents with this type of aircraft, any safety directives and the company’s maintenance records as it tries to learn why the plane hit the water.

“Early in the investigation every possibility is on the table,” Wallace said.

One accident that will be of interest is the 2019 crash of the same model of floatplane in Manitoba, Canada, he said. A DHC-3 Otter with a pilot and two passengers was headed to Family Lake when the plane’s right wing came off. The aircraft took a nosedive into the lake, killing everyone onboard, according to the accident report.

Following the lead of Canadian authorities, the FAA issued an Airworthiness Directive for these planes in March that required inspections of lugs, bolts and plates to ensure the wing strut is secure, according to the agency’s order.

“Failure of a wing strut could result in a catastrophic in-flight breakup of the wing,” the report said.

Coast Guard searchers found “minimal debris,” Giard said.

Without a clear picture of the actual crash, and not knowing whether it exploded on impact or immediately sank to the sea floor, 150 to 200 feet (45-60 meters) below, it’s difficult to know what happened to the plane, he said.