MIAMI (CBSMiami/AP) – Family members of six American oil executives jailed in Venezuela have accused Nicolas Maduro’s government of “forced disappearance” after the men were inexplicably missing for the scheduled start of their trial on Wednesday.

Veronica Vadell said that lawyers for her father, Tomeu Vadell, and the five other executives from Houston-based Citgo had been waiting at a Caracas courthouse for more than six hours for the men to be transferred by the nation’s intelligence police.

In a message posted on social media, she demanded stakeholders on all sides work to resolve the “hostage case” immediately.

“Why is there a delay? Where are the men?” she wrote.

The six oilmen were under house arrest when they have abruptly rounded up without explanation two weeks ago.

Since then they’ve remained in isolation, with no access to their families or lawyers.

The arrest took place the same day opposition leader Juan Guaidó met with President Donald Trump at the White House, fueling speculation the detention was politically motivated.

It’s not clear why the SEBIN police never transferred the men from the Helicoide jail in Caracas where they are believed to be held.

Maduro’s chief prosecutor, Tarek William Saab, confirmed to The Associated Press on Wednesday that all was set for the trial to begin.

The six men were hauled away by masked security agents while at a meeting in Caracas just before Thanksgiving in 2017.

They had been lured to Venezuela in order to attend a meeting at the headquarters of Citgo’s parent, state-run oil giant PDVSA.

The group flew out on a corporate jet.

They included Vadell, vice president of refining; Gustavo Cardenas, head of strategic shareholder relations as well as government and public affairs; Jorge Toledo, vice president of supply and marketing; Alirio Zambrano, vice president and general manager of Citgo’s Corpus Christi refinery; Jose Luis Zambrano, vice president of shared services; and Jose Angel Pereira, the president of Citgo.

The men are awaiting trial on corruption charges stemming from a never-executed plan to refinance some $4 billion in Citgo bonds by offering a 50% stake in the company as collateral.

Prosecutors accuse the men of maneuvering to benefit from the proposed deal.

But many believe the men, five of whom are naturalized U.S. citizens and the other a legal resident, are being held as political bargaining chips as relations between the U.S. and Venezuela have deteriorated. They cite as evidence of irregularities the decisions by the initial judge to postpone 15 straight times a preliminary hearing.

U.S. Vice President Mike Pence in April called for the men’s release after meeting with family members at the White House.

“We are going to stand with you until they are free and until Venezuela is free,” he said at the time.

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)