This is the third and final installment in a series on the Trump administration's controversial "Remain in Mexico" program and its impact on thousands of asylum-seeking families. Read parts one and two here. 


El Paso, Texas — In the late winter and spring of this year, the migrant shelters in this Texas border city were overwhelmed. Local immigration authorities were releasing hundreds of asylum-seeking families, most of them from Central America.

"We were dealing with 800, 900, 1,000 people that were being released to us per day," Ruben Garcia, the executive director of the Annunciation House network of shelters, told CBS News.

For years, Garcia and his organization have been communicating with the Immigration and Customs Enforcement (ICE) and Border Patrol units in this sector to ensure the families released by the agencies get temporary housing and assistance while they arrange for travel to reunify with family members living across the U.S. 

Although he acknowledged that helping such large groups of migrants was a monumental task, Garcia stressed that his organization and local partners were able to do so, including by paying more than $1 million in hotel room fees when there was no space at the shelters. Over the past 10 months, he said Annunciation House has housed more than 150,000 migrants, most of whom left El Paso within two days of their release from detention.

In recent months, however, the U.S government has been keeping most asylum seekers on the other side of the border, in Ciudad Juárez, Mexico — where advocates like Garcia say they can't help them. 

Along with amped up immigration enforcement by the Mexican government, the administration has directly pointed to this policy as one the main reasons apprehension numbers along the southern border have dwindled in the past two months from the height of the recent surge in May. The Annunciation House is now receiving between 50 and 150 migrants per day — a sharp drop from the 1,000 peak — and has closed all but two shelters.

But Garcia said he "utterly" disagrees with the notion that the "Remain in Mexico" policy, formally called the Migrant Protection Protocols (MPP), should continue because it has contributed to lower numbers of families staying at his shelters. 

"I don't accept that we should do MPP because we need to lighten the load, be it on us or Border Patrol," he said during an interview at the Casa del Refugiado, a former warehouse that now serves as the main shelter for most migrant families released by immigration authorities in the El Paso area. "My response to that is: when you have human need, you invite more people to help respond to that human need."

Garcia's main concerns about the policy are shared by attorneys, other advocates in the El Paso area and even some of the asylum officers interviewing migrants in the MPP program who express fear of returning to Mexico. They've all denounced the policy as one that forces desperate migrants — many of them vulnerable families with small children and single women — to wait months in Mexico, where they struggle to find housing and lawyers and sometimes face persecution.  

"It's especially dangerous for refugees," Garcia said, referring to Ciudad Juárez, as locals refer to the city, one of the most dangerous in Mexico. "There are gangs that would kidnap a refugee and hold the refugee for ransom: 'I've got this woman and her child from Guatemala, Honduras, El Salvador. Give me the number for relatives. Send me $2,000, send $4,000, send me $5,000 or I'll kill them.'"

According to the State Department, violent crime and gang activity are "widespread" in Chihuahua, the state where Ciudad Juárez is located. The U.S. has also recently begun to place asylum seekers in the MPP program when they arrive near Brownsville and Laredo, returning them to Tamaulipas, one of five Mexican states the State Department warns travelers not to visit because of rampant crime and the risk of being kidnapped.

"They are a marketable commodity and our State Department knows that," Garcia added, referring to asylum seekers. 

© 2019 CBS Interactive Inc. All Rights Reserved.