Greece will hold trials for assistance workers for refugees.

In what experts have dubbed "the largest case of criminalization of solidarity" in Europe, 24 defendants are set to go on trial on the Greek island of Lesbos on Tuesday for their work with refugees.

Rights organizations have also criticized the court processes as chaotic, perplexing, and ridiculous.

Some of the 24 are accused of spying and forgery, while others are charged with unauthorized radio frequency listening.

According to Human Rights Watch, one of the numerous organizations that have criticized the trial, while some defendants are aware of the allegations they are facing, others are not since their names are recorded in official records by number rather than by name.

All of the defendants, who come from a variety of nations, including Greece, contest the accusations made against them.

The case is a part of a conflict between Greek authorities and civil society that has gotten worse and could last months to resolve.

Greece, which throughout the years has taken in thousands of people escaping conflict and poverty, has cracked down on and scrutinized groups and activists in an effort to prove some of them were complicit in smuggling since the height of the refugee crisis. Meanwhile, human rights organizations have accused the Greek government of mistreating refugees and forcibly returning them to the sea.

Sarah Mardini, the sister of Olympic swimmer Yusra Mardini, is one of the defendants in the trial that began on Tuesday.

The Syrian twins received praise for helping to save 18 other travelers in 2015 when dragging a sinking refugee dinghy to safety while traveling from Turkey to Greece. The Swimmers, a Netflix original film, was later made from their narrative.

Sarah returned to Lesbos to assist migrants who were coming to the island's shores after obtaining refugee status in Germany. Yusra went on to compete in the Olympics in Rio de Janeiro in 2016 as a swimmer.