U.S. authorities on Thursday announced the indictment of a Guatemalan national who they say helped coordinate a human smuggling effort that ended with 53 migrants dead in a sweltering tractor-trailer in Texas.

Rigoberto Román Mirando Orozco is charged with six counts of migrant smuggling resulting in death or serious injury in the deadliest attempt from the U.S.-Mexico border. Authorities alleged he can be connected to four of the migrants in the trailer, three of whom died.

Arrests related to the 2022 deaths in San Antonio have climbed to more than a dozen and now stretch to Central America after years of investigations.

On Wednesday, Guatemalan officials announced the arrests of seven people accused of helping smuggle the migrants, including Mirando Orozco, the alleged ringleader whose extradition had been requested by the United States, Interior Minister Francisco Jiménez told The Associated Press.

Jiménez said the arrests were made possible after 13 raids in three of the country's departments. Police also seized vehicles and cash and rescued other migrants during the operations, Guatemalan officials said in a statement.

"This is a collaborative effort between the Guatemalan police and Homeland Security, in addition to other national agencies, to dismantle the structures of human trafficking, one of the strategic objectives of the government President Bernardo Arévalo in order to take on the phenomenon of irregular migration," Jiménez said.

Six people were charged previously, including Homero Zamorano Jr., who authorities say drove the truck, and Christian Martinez. Both are from Texas and were arrested shortly after the migrants were found. Martinez has since pleaded guilty to smuggling-related charges, while Zamorano pleaded not guilty and is awaiting trial.

Four Mexican nationals were also arrested in 2023.

Authorities say the men were aware that the trailer's air-conditioning unit was malfunctioning and would not blow cool air to the migrants trapped inside during the sweltering, three-hour ride from the border city of Laredo to San Antonio.

When the trailer was opened in San Antonio, 48 migrants were already dead. Another 16 were taken to hospitals, where five more died. The dead included 27 people from Mexico, 14 from Honduras, seven from Guatemala and two from El Salvador.

Authorities allege that the men worked with human smuggling operations in Guatemala, Honduras and Mexico, and shared routes, guides, stash houses, trucks and trailers, some of which were stored at a private parking lot in San Antonio.

Migrants paid the organization up to $15,000 each to be taken across the border. The fee would cover up to three attempts to get into the country.

Guatemalan officials accuse the group of housing and transferring hundreds of migrants to the United States over several years.