Q COSTA RICA (by NatalieOlivo, Law360) U.S. investors who claim Costa Rica owes them more than us$95 million for shutting down their beachfront villa project have reiterated before a World Bank tribunal their contention that the Central American nation has failed to back up allegations the project involved construction on protected wetlands, in a letter obtained by Law360 on Thursday.

In the unpublished letter to the tribunal obtained by Law360, the investors again argued that Costa Rica has failed to support its allegations that the properties, referred to as the Las Olas project, contain protected wetlands that required a halt on construction. The investors, who have said the wetland claim was “unfounded and arbitrary,” are seeking US$95.4 million for the nixed project.

“The Las Olas project was fully, and legally, permitted by the appropriate government agencies,” David Aven, one of the investors, told Law360 on Thursday. “It was then shut down, nine months into infrastructure construction, based upon a false claim of wetlands.”

The letter, which is dated April 26, was submitted to the tribunal shortly before the International Centre for Settlement of Investment Disputes on Tuesday republished the investors’ 300-plus-page brief. In that filing, the investors said that a local municipality’s work on the project site undermines the country’s argument regarding the wetlands.

More: Costa Rica Says Default Against It Should Be Vacated

According to the brief, which was submitted March 13 and first publicly filed on April 20, the investors said they had recently learned that the Costa Rican Ministry of Transport and Public Works, or MOPT, is carrying out work to replace a sewage system on the Las Olas project site where the purported wetlands are located. When the investors’ counsel asked Costa Rica if it had conducted environmental assessments, the country cited an exception for works involving street repairs.

But Costa Rica can’t have it both ways, the investors said. Either the property near the MOPT works is a wetland and requires an environmental assessment, or — as the investors, their environmental expert witnesses and others have maintained all along — it is not a wetland, according to the brief.

Costa Rica has claimed that the investors, who also allege that the country brought baseless criminal charges against them for building on protected lands, deliberately misled government authorities on the environmental impact of their project and undertook work without the proper permits, displaying a “brazen disregard” for Costa Rican law and environmental standards.

But during a February hearing, the transcript of which the ICSID released the following month, the investors questioned why the Central American nation failed to produce any witnesses from the country’s environmental authority, the Ministry of Environment and Energy’s National Environmental Technical Secretariat, or SETENA.

Aven told Law360 that he had raised this issue during his cross-examination in a December hearing as well, when he asked the tribunal where his accusers were.

“Why isn’t someone at this hearing from SETENA to tell the panel directly that I duped them?” Aven asked. “Costa Rica’s entire case was built on allegations, assertions and hearsay that the government continually tried to advance as evidence.”

Costa Rica, meanwhile, reiterated during the December hearing, also publicized by the ICSID in March, its argument that the reality of the investors’ situation is much different than the picture they’ve painted. The investors made unlawful misrepresentations on the conditions of the land, misleading Costa Rican authorities into condoning their false environmental assessments and causing those authorities to issue unlawful permits, Herbert Smith Freehills LLP partner Christian Leathley, who is representing Costa Rica, argued.

They were also able to evade critically important environmental controls by unlawfully fragmenting the land, he said.

The investors filed a notice of arbitration in January 2014, arguing that they obtained all of the necessary permits for building luxury beachfront villas, midrange townhouses, smaller villas and a beach club for the Las Olas project. They claim that Costa Rica halted construction following an “unfounded and arbitrary” determination that the property had wetlands and a forest. In reality, the investors said, the stop-work order was based on their failure to pay a $200,000 bribe to a government official.

The country then brought criminal charges against them as a form of intimidation, the investors said.

The country’s Ministry of Foreign Trade shot back last year, telling the ICSID tribunal that the investors had based their arguments against the country on a serious misinterpretation of Costa Rican environmental law and drawn warped conclusions from a blatant misrepresentation of facts.

Counsel for Costa Rica and the investors declined on Thursday to comment. The investors are represented by Vinson & Elkins LLP and Todd Weiler.

Article originally appeared on Law360.com -Legal News and Analysis.