HONOLULU (AP) — More than two dozen Thai farm laborers on Monday signed a letter to U.S. Attorney General Eric Holder lamenting the dismissal of human trafficking charges against people accused of exploiting them.

The letter expresses regret that the largest-ever human trafficking case brought by the U.S. government ended without going to trial. It tells Holder the workers had faith in the U.S. justice system.

"Some of us spent hours upon hours detailing our experience over and over again to federal agents," the letter said. "Many of us still had the documents needed to prove everything we said was true."

Global Horizons, of Los Angeles, was accused of manipulating 600 Thai workers it placed in farms across the United States.

The company's attorney in Honolulu, Michael Green, last month called the dismissal a "moral victory."

Chanchanit Martorell, executive director of the Thai Community Development Center in Los Angeles, said it's contradictory for prosecutors to tell the center its clients were victims of a severe form of trafficking but that they can't prove the charges beyond a reasonable doubt.

"This outcome is simply not credible and is unacceptable," she said in a statement.

Martorell said the workers don't want to be forgotten and left to the wayside after what they've been through.

The trial was scheduled to be held this month in Honolulu.

But last month, federal prosecutors requested a dismissal of the case against two executives of Global Horizons Manpower Inc., the CEO, Mordechai Orian, and the director of international relations, Pranee Tubchumpol.

They were accused of exploiting hundreds of farm workers from Thailand by putting them into debt, confiscating their passports and threatening to deport them.

The case was in jeopardy after federal prosecutors abruptly dropped similar accusations against Alec and Michael Sou, brothers and owners of Hawaii's Aloun Farms, last year. That case prompted an investigation that found the federal government wouldn't be able to prove the charges in the Global Horizons case, according to the dismissal order.

The case against the Sous fell apart when lead prosecutor Susan French conceded that she inaccurately stated to a grand jury that workers couldn't be charged recruiting fees when they traveled to Hawaii in 2004. The law was changed in late 2008 to prohibit recruiting fees.

French stepped down from the prosecution team shortly afterward because of unspecified health problems.