Federal agents have arrested four people accused of smuggling 131 illegal immigrants found at a "stash house" in south Texas, a U.S. Immigration and Customs Enforcement official said Wednesday.
The immigrants were also detained Tuesday after a raid at a house near Alton, Texas, about eight miles north of the U.S.-Mexico border, ICE spokeswoman Nina Pruneda said.
The people at the house were from Mexico and Central America, and did not require medical attention, she said.
The Monitor newspaper, which covers the Rio Grande Valley, said Salvador Hernandez, 52, had just left his house with his elderly parents when the normally quiet neighborhood was suddenly surrounded by ICE agents.
“I have been living here for 28 years and have never seen anything like that happen,” he told the paper.
Border Patrol agents in the Rio Grande Valley, which straddles the southern tip of Texas along the Gulf Coast, have seen the number of so-called "stash houses" used to house illegal immigrants roughly double since October 2011, according to agency figures.
'Welcome to Hell'
In one of the more brutal recent cases, two men pleaded guilty on Wednesday to harboring 115 immigrants -- some without food or water for days -- in a cluster of stash houses in Edinburg, Texas.
Vicente Ortiz Soto and Marcial Salas Gardunio, both 23-year-old Mexican citizens, pleaded guilty to conspiracy to harbor aliens on Wednesday in U.S. District Court, according to a statement from U.S. Attorney Kenneth Magidson, who represents the Southern District of Texas.
Several of the immigrants required medical attention after authorities found dozens of them locked inside a crowded, hot, ramshackle house, according to a criminal complaint filed in the case.
One immigrant told ICE agents that Salas would greet new arrivals with "Welcome to Hell" when they arrived at the residence and threatened to beat or kill them if they did not remain quiet, court papers state.
Ortiz admitted to driving immigrants to the stash houses from the border and selling them snacks.
Each man faced up to 10 years in prison and a $250,000 fine at a sentencing hearing set for July.
More content from msnbc.com and NBC News:
- Deep-sea aliens hitched ride by submarine into pristine area
- More military tombstones found in backyard
- La. school psychologist quits over allegedly racist online posts
- Senators grill Secret Service boss on prostitution scandal
- Man arrested for drunk driving with zebra, parrot in truck
- Video: Parents outraged over bike ride suspensions
- Staff bled $44 million in gifts from heiress, suit says