Four men are facing federal charges, accused of smuggling thousands of people into the US from Guatemala in what officials call “one of the largest human smuggling rings in the nation.”

Federal agents are still pursuing one of the four men, who they say threatened to kill an investigative agent and his family as officials served search warrants on Friday.

Acting US Attorney for the Central District of California Joseph T. McNally announced the charges at a Monday news conference in Los Angeles. The organization smuggled around 20,000 people into the country from 2019 to 2024, the indictment states.

“The offenses alleged in the indictment show a criminal group that acted with callous disregard for a nation’s immigration laws and no regard for the immigrants that they smuggled,” McNally said. “They held individuals smuggled hostage for months, threatened them and their family members with violence.”

The four defendants are all undocumented immigrants from Guatemala, the indictment states. They face charges of conspiracy to bring aliens to the United States, transport aliens in the United States, and harbor aliens in the United States for private financial gain and resulting in death; transporting aliens in the United States for private financial gain and resulting in death; hostage taking; and criminal forfeiture. Each faces up to life in prison and the possibility of the death penalty if convicted, according to McNally.