Criminal networks with Latin American roots, such as MS-13 and the 18th Street gang, are using the administration's open-door policy at the border to slip in recruits that are causing a huge spike in murder and violence throughout the nation, according to an immigration expert.

Testifying Thursday at a House hearing on the border surge of young Latinos, the expert said, "Established gangs have been able to transfer an unknown number of experienced foot soldiers from Central America to help colonize new criminal territory in the United States."

Jessica M. Vaughan, the policy director for the Center for Immigration Studies, told the House Judiciary Committee's Immigration and Border Security subcommittee that "the tide of new young people, many of whom have already been exposed or involved in street gangs at home, has provided a huge pool of new recruits for the gangs here. Gangs such as MS-13 and 18th Street are enjoying a brutal revival in certain parts of the country and are establishing themselves in new places."

Jessica M. Vaughan discussing the issues of visa overstayers.

She added, "Violent transnational gangs such as MS-13 have taken full advantage of the Obama administration's welcome mat to swell their ranks here, contributing to a noticeable spike in gang violence in certain localities – with tragic results."

Vaughan offered dramatic details of the results of the "catch and release" policy employed by the administration as it grabs illegal immigrants crossing the border, then lets them go on a promise they will return for court hearings — which few make good on.

In the testimony provided in advance of the hearing to Secrets, she said:

— In Frederick County, Md., 20 miles from the White House, crime has jumped since about 265 illegal unaccompanied Central American minors were placed there. Gang fights in schools are now common and one of the older MS-13 "shot callers" was approved for President Obama's Deferred Action for Childhood Arrivals (DACA) program.

— In Boston, cops just arrested 56 MS-13 gang members, many who arrived in the surge of younger Latinos. Some have been linked to teen murders in an initiation rite, trying to prove themselves worthy of full membership.

— In Loudoun, County, Va., home to Washington's Dulles International Airport, three unaccompanied minors who arrived in 2013 have been indicted for the gang-related murder of 17-year-old Danny Centeno Miranda, also an unaccompanied minor living with his uncle.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com.