There's been a shroud of mystery around the sudden release of thousands of immigrants from detention just days before the sequester was scheduled to take effect. Department of Homeland Security Secretary Janet Napolitano denied that the release had much to do with the budget cuts that all federal agencies have been facing.

(AP Photo/Alan Diaz) (AP Photo/Alan Diaz)

But in a Congressional hearing on Thursday, DHS's chief of Immigration and Enforcement confirmed that austerity did, in fact, prompt the agency to release 2,228 immigrants for "solely budgetary reasons," some of whom were convicted of crimes ranging from drunk driving and traffic offenses to financial crimes categorized as aggravated felonies.

"With the strong possibility of sequestration, ICE officials managed the detention population in order to ensure that ICE could operate within the appropriations provided by Congress," ICE chief John Morton told a House Appropriations subcommittee. "I regret that the timing of our releases caught many by surprise."

Morton explained that ICE was actually detaining more immigrants than they were mandated by Congress to have beds for when it made the decision to release them en masse. Currently, ICE is required by law to have 34,000 beds for detained immigrants who are facing the possibility of deportation. In early February, ICE was detaining more than 35,000 immigrants, "including many who did not require detention by law," Morton explained. Even before the sequester took effect — cutting $300 million from ICE's budget over the next seven months — the agency had been facing the uncertainty of a Continuing Resolution that's scheduled to expire at the end of March. So over the course of three weeks in February, the agency released 2,228 immigrants into more cost-effective forms of supervision — bond, ankle-bracelets, phone-monitoring, etc. — while they waited for their deportation cases to be resolved.

Under pointed questioning from lawmakers, Morton acknowledged that some of the immigrants released had previous criminal convictions, including multiple drunk driving offenses and 10 immigrants who had committed offenses attached to the most severe deportation penalties. But he stressed that those offenses were generally minor, in many cases happening years prior, and that each case was individually reviewed to ensure that "serious criminal offenders and others who pose a threat to the national security or public safety" remained behind bars.

The other complicating factor, however, is the fact that spending at agencies like ICE is so heavily focused on personnel. In a climate of austerity, it's hard to make cutbacks without reducing the number of immigration agents, investigators, and so forth, as I've reported before. Other than immigrant detention, "the only other big account is to reduce the activities of our domestic investigations," Morton explained, which would undermine the agency's ability to go after serious offenders like "child pornographers and drug smugglers."

Morton's statements are likely to frustrate immigration and civil-rights advocates who've questioned why such immigrants were held in detention in the first place. But Republicans at the hearing who had been particularly furious about the initial news of the release seemed to be satisfied with Morton's explanation, though they believed they should have been filled in earlier.

"If we were given that information, that noted this person [who had been released] had a simple assault 10 years ago, when they were 19-years-old, I think we have enough common sense to realize that's an extenuating circumstance," said Rep. John Carter (R-Tex.), who had noted earlier. "It's not like we're just some crazy people who want to lock everybody up."