JUAREZ, Mexico (Border Report) – The arrest of seven men driving on a south Juarez highway in the middle of the night is providing authorities a glimpse of how transnational migrant smuggling organizations operate on the Mexican side of the border.

Late Wednesday, Chihuahua state police officers patrolling the Juarez-Casas Grandes Highway noticed a caravan of five vehicles driving west toward a desolate road that leads to the Mexico-New Mexico border.

The officers called for backup and stopped the five vehicles just before they took the San Jeronimo exit. They found the drivers were transporting 20 migrants in the cars and a rope ladder, the state police said in a statement Thursday.

The alleged smugglers told Mexican authorities they were headed to the Chihuahua-New Mexico border to help 14 citizens of Bolivia, Guatemala and Honduras, as well as six others from Southern Mexico, get over the border wall and enter the United States illegally, the state police said.

The group of smugglers working for a criminal organization police did not immediately identify range in ages from 19 to 46; three are Juarez residents but the other four are out-of-towners.

The state police said they released the six Mexican migrants to a Juarez shelter but turned over the foreign nationals to National Immigration Institute agents. The five vehicles and the ladder were impounded.

Last week, the Mexican Attorney General’s Office filed charges against three men and a woman who were allegedly bringing to Juarez up to 150 migrants a week from safe houses in Mexico City and Guanajuato. The AG’s Office said the suspects belong to a transnational criminal organization engaged in smuggling Turks, Brazilians and Central Americans to the United States.

The Chihuahua state police also continues to investigate the murder of two web-platform drivers and four passengers found on the San Jeronimo highway in late October. Authorities found a cardboard sign at the scene saying the victims were polleros (migrant smugglers).

That’s in addition to the discovery of numerous migrant safe houses in the city since last September.

Border security experts such as Victor M. Manjarrez Jr. of the Center for Law and Human Behavior at the University of Texas at El Paso say the Mexican drug cartels make hundreds of millions of dollars off migrant smuggling.

“It is a huge moneymaker. When you look at these plazas,” he said during an earlier interview by the border wall in Sunland Park, New Mexico, pointing toward Juarez, “we forget these cartels make a lot of money. […] not smuggling dope, not human trafficking but simply charging people fees for using their real estate.”

The Chihuahua-New Mexico border has long been a hotspot for illegal entries by migrants amenable to Title 42 expulsions, primarily Mexicans and Central Americans.

“These folks that are crossing today, tonight, they don’t decide, ‘that’s a nice place to pick.’ Their guides, their smugglers say, ‘you’ll cross through here because I already paid the fees,'” Manjarrez said.