BANGKOK (Reuters) - The Thai navy on Saturday boarded the floating cabin of a fugitive U.S. citizen and his Thai girlfriend, both prominent members of the “seasteading” movement who possibly face the death sentence for setting up their offshore home.

Thai authorities have revoked the visa of bitcoin trader Chad Elwartowski and charged him and his partner with violating Thai sovereignty by floating the cabin 14 nautical miles off the west coast of the Thai island of Phuket.

The cabin had been promoted as the world’s first seastead by the group Ocean Builders, part of a movement to build floating communities beyond the bounds of nations as a way to explore alternative societies and governments.

“I was free for a moment. Probably the freest person in the world,” Elwartowski posted on Facebook on April 13, days before the Thai navy raided his vessel.

Elwartowski, 46, was not on board having apparently fled after a surveillance plane flew overhead the previous day, along with his partner Supranee Thepdet, whose Facebook page describes her as a “Bitcoin expert, Trader, Chef, seastead Pioneer”.

The U.S. Embassy in Bangkok said Elwartowski had engaged a lawyer and was being provided with appropriate assistance.

The Royal Thai Navy had planned on Saturday to seize the structure and tow it back to shore for use as evidence.

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In a video posted last month detailing the construction of the floating home, Elwartowski said 20 more similar homes would be up for sale to form a community.

Elwartowski and Ocean Builders say the vessel was in international waters and beyond Thailand’s jurisdiction. But Thai authorities say the structure is in its 200-mile exclusive economic zone and therefore a violation of its sovereignty.

A Thai navy task force on Saturday inspected the floating home as it prepared to tow the structure back to Phuket.

LEGAL PROCESS

“We will invite technical units and officials who have inspected the object to consult on the methods of towing to minimize damage,” Captain Puchong Rodnikorn, chief of staff of the Operations Squadron of the Third Naval Area Command, said.

“Once the sea house reaches the shore, the owner of this house can come to inspect it, as well as come forward to the Thai authorities in order to prove themselves in the legal process,” he said.

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The navy said it had evidence that the floating home was built in a private boatyard in Phuket and the couple wanted to establish a “permanent settlement at sea beyond the sovereignty of nations by using a legal loophole”.

It said the action “reveals the intention of disobeying the laws of Thailand ... and could lead to a creation of a new state within Thailand’s territorial waters,” adding this would undermine Thailand’s national security as well as the economic and social interests of maritime nations.

In an email reply to Reuters, Elwartowski referred all questions to the Seasteading Institute and pointed to online statements from the Ocean Builders website.

Elwartowski and Supranee are members of Ocean Builders, which has denied they were planning to set up an independent state or “micro nation”.

The group said the pair did not build, invest in or design the floating home themselves, but were “volunteers excited about the prospect of living free”.

According to Ocean Builders, the concept of seasteading has been discussed for years but the cabin Elwartowski and Supranee lived on was the first attempt at living in what it described as international waters.

Other groups, such as the Seasteading Institute, which was originally backed by PayPal co-founder Peter Thiel, have sought to build floating cities with the cooperation of host nations.