Federal agents are perfecting the science of rooting out fraudulent family units seeking asylum at the U.S. border, and Acting ICE Director Matthew Albence offered some statistics on the progress in Washington, D.C. on Friday.

Federal law currently requires the government to release anyone with a child from custody within 20 days, which has created a thriving market for smugglers who rent, sell and recycle children for expedited processing.

Last May, ICE Homeland Security Investigations launched a DNA testing program as illegal border crossings skyrocketed to more than 132,000, which included more than 84,000 posing as family units. So far, Albence said, officials have identified 700 fake families, as well as 1,500 others attempting to use fake documents to prove family ties, The Epoch Times reports.

Albence offered several examples of how illegal immigrants attempted to bamboozle border agents.

In one case, agents conducted a DNA test on a woman with a 2-month-old child to prove a family relationship, but the cheek swab used for the child repeatedly returned inconclusive results.

“They did three or four tests and the DNA tests for the child kept coming back inconclusive. In fact, they kept coming back with two different strains of DNA, which isn’t humanly possible,” Albence told reporters.

“The mother was spitting into the child’s mouth, to put her DNA into the child so they could be released as a family unit,” he said. “That’s what’s going on down at the border. That’s the humanitarian crisis we’re talking about, and we’re trying to deal with it.”

In another instance, a 51-year-old Honduran man confessed to purchasing a 6-month-old baby for $80 on his way through Guatemala when confronted with a DNA test, Albence said.

He said more than 1,000 have faced prosecution for “fraud related to crimes including immigration crime, identity and benefit fraud, alien smuggling, human trafficking and/or child exploitation,” the Times reports.

U.S. Customs and Border Protection statistics show apprehensions – illegal immigrants arrested trying to sneak in between ports of entry –  have nosedived at the border over the last seven months, with family units accounting for a mere 8,602 apprehensions out of a total of 32,858 in December.

Likewise, the numbers of inadmissibles – illegal immigrants who present themselves at ports of entry – is also trending downward, with a total of 7,762, including 3,462 family units, in December.

The decline is undoubtedly tied to a variety of initiatives from the Trump administration to slow the tide of Central American migrants pouring across the border in recent years, from pressuring Mexico to agree to do more to stop illegal migrants, to a new “Remain-in-Mexico” asylum policy, to the improved border screening, to more than 100 miles of new and improved border walls.

Last week, a new migrant caravan departed Honduras and trekked through Guatemala before coming to a standstill at the Mexican border, where the Mexican National Guard lined up to resist the invasion.

Mexican officials arrested hundreds that have attempted to cross in the days since and have already begun sending many back to Honduras, The American Mirror reports.

About 800 migrants who waded across the river before daybreak on Thursday were surrounded by Mexican soldiers hours later as they walked down a rural highway, where they were rounded up and bused to a processing center for deportation.