A family walks by a wall covered by a symbol from the Mara Salvatrucha, or MS-13, gang in Ilopango, El Salvador. (Esteban Felix/AP)

Members of the Senate Judiciary Committee grilled top federal immigration officials Wednesday over how to prevent the violent street gang MS-13 from targeting unaccompanied minors who have entered this country illegally.

Citing a recent Washington Post report linking a surge in MS-13 violence around the country to its recruitment of unaccompanied minors, Sen. Chuck Grassley (R-Iowa) said federal officials were not keeping close enough track of the youth.

“The government’s total failure to establish an efficient process and meaningful oversight of the placement of these children has led to the current MS-13 crisis,” said Grassley, the committee chairman.

Testifying at the hearing were top officials from U.S. Customs and Border Protection, Immigration and Customs Enforcement, the Department of Justice and the Office of Refugee Resettlement, the agency in charge of reuniting unaccompanied minors with relatives in the United States.

“No one takes responsibility for these children after they are placed with a sponsor,” Grassley said. “Your agencies repeatedly pass the buck to each other. As a result, children are allowed to disappear. When these children disappear without any supervision, they are vulnerable to join dangerous gangs like MS-13.”

Senate Judiciary Committee chairman Sen. Chuck Grassley (R-Iowa) (Charlie Neibergall/AP)

The Post investigation published earlier this month found that at least 14 young people placed by ORR were caught up in MS-13 violence after their moves to the United States. That includes eight charged in connection with slayings.

Wednesday’s hearing was the first time that some of the agencies had provided statistics on unaccompanied minors suspected of gang involvement.

Since October of 2011, Customs and Border Protection has apprehended approximately 5,000 individuals — mostly adults — with confirmed or suspected gang affiliations, Acting Chief Carla Provost testified.

That number includes 159 unaccompanied minors, 56 of whom were suspected or confirmed to be affiliated with MS-13, she said.

The agency apprehended a total of about 250,000 unaccompanied minors during that time period, Provost said.

By law, border agents have 72 hours to pass unaccompanied minors to ORR. Agents are instructed to notify the refu­gee resettlement office and the Department of Homeland Security when they suspect an unaccompanied minor who has been placed in U.S. custody belongs to a gang.

Scott Lloyd, the director of ORR, told the senators that his agency had identified a similarly small share of unaccompanied minors with gang involvement.

A June 9 ORR review found that of the 138 unaccompanied minors in its most secure facilities, 35 were voluntarily involved in gangs, including MS-13. Another four minors said they had been forced into a gang.

It’s unclear how many unaccompanied minors with admitted gang ties have been released by ORR, or if any of them have been involved in crimes after their release. The agency says it has released “a small number” of children with “minimal” gang affiliation to live with relatives.

Earlier this month, ORR was forced to release a 17-year-old unaccompanied minor who admitted to spending three years in MS-13 in Honduras. A federal judge ordered his release, ruling that his rights had been violated.

“Nobody can really tell us how many of these children are being trafficked, become recruited as gang members or anything of that nature, can you?” asked Sen. John Cornyn (R-Texas).

Lloyd replied that “the best we can do is to scrutinize the sponsor ... and also while the [minor] is in our care, to monitor any of their behavior to figure out if they may be prone to criminal activity.”

He said his agency had recently instituted policies to prevent young people from being recruited by MS-13, including training employees to identify signs of MS-13 membership during follow-up phone calls with minors who have been released to family members.

But he said ORR was hamstrung by federal laws restricting those follow-ups as well as “limited resources.”

“You could use some help from the policymakers, in my view,” Cornyn said.

“We’d welcome that,” Lloyd replied.