Thelma and Don Christie (center) of Tucson demonstrate against the arrival of undocumented immigrants in Oracle, Arizona, July 15, 2014. Reuters

An Arizona judge found 12 immigration activists guilty Tuesday relating to their arrests during a 2013 protest that stopped two buses carrying dozens of illegal immigrants on their way to court in Tucson to face deportation charges. Judge Susan Bacal ruled that the activists were guilty of being a public nuisance and obstructing a highway or thoroughfare.

During the trial, Bacal dismissed four other charges against the group, including hindering prosecution, criminal trespass, obstructing a government order and disorderly conduct. A sentencing hearing is scheduled for sometime in July. They face up to four months in jail, according to the Tucson Sentinel.

The activists were protesting the federal government's fast-track immigration court, known as Operation Streamline, when they were arrested. They chained themselves to the buses' front wheels for five hours before police used power tools to cut them free. The protesters said Operation Streamline violates immigrants' civil rights. Most of the 70 immigrants on the buses were deported days later. Federal officials said the legal program cuts down on recidivism for illegal entry.

Defendant Gabriel Schivone, a 31-year-old writing tutor at the University of Arizona, told the Phoenix New Times after the verdict that he was "mainly thinking of the immigrants who don't get the privilege of a fair trial."

Operation Streamline was established in 2005. Under the program, illegal immigrants are rounded up near the border and taken straight to court, where they are sentenced in about an hour. Critics argue that the program denies immigrants a defense process. "I’m just appalled," Isabel Garcia, a criminal defense lawyer and immigration activist in Tucson, told the Washington Post last year. "This program is endangering our very justice system."