Thousands of illegal immigrants convicted of serious crimes—including rape, child molestation and kidnapping—have been released in the United States by the Department of Homeland Security (DHS) and the agency doesn’t bother keeping track of the alien convicts.

The DHS agency responsible for removing dangerous illegal aliens, Immigration and Customs Enforcement (ICE), simply releases sex offenders when they complete their criminal sentence and fails to monitor or force them to register with local authorities in the communities where they resettle. The incredulous story of this outrageous system comes via an investigative series published this week in a Boston newspaper that sued the government for the records. It includes a database of criminals that one former federal prosecutor calls “chilling.” The offenders are “dangerous and predatory individuals who should not be prowling the streets,” the prosecutor says in the article. “In fact, they should not be in the United States at all.”

But our famously inept Homeland Security officials simply let these monsters loose in unsuspecting communities, even though one law enforcement agency cited in the series calls the illegal immigrant cons “the worst of the worst.” At the very least, ICE is supposed to assure that the thugs register with local authorities as sex offenders, but the agency doesn’t even bother to do that. Instead, once ICE frees the offenders, agency officials often lose track of them despite outstanding deportation orders. It’s like negligence on steroids.

One disturbing case mentioned in the article focuses on a Cuban national named Santos Hernandez Carrera, who raped a woman at knifepoint and spent roughly half his life in jail. He was supposed to stay in custody until he could be deported, but instead the feds released him and lied about it. The public sex offender registry said Carrera had been deported though he never was, according to the news story. The reporters working on the series actually tracked the illegal immigrant rapist down in Florida. Local authorities assert that ICE never informed them that they had released sex offenders in their jurisdiction even though, by law, the convicts must register as sex offenders with local police.

ICE offers a weak explanation for its egregious policy, claiming that the criminals cannot be deported because their home country won’t take them back. Once they complete a federal or state prison sentence, ICE can only hold them for six months unless they are determined mentally ill and dangerous. It certainly appears that the agency is disregarding that law to lessen its load. In fact, the article reveals that for years doctors warned federal immigration officials not to take their eyes of Carrera, the Cuban rapist with a documented history of mental illness and violence. ICE could have kept him in custody but chose not to.

In all, the newspaper identified 424 released illegal immigrants convicted of sex-related crimes in the records obtained under the lawsuit. Around half appeared in the national public sex offender registry as required by law. Of the registered sex offenders, 53 failed to re-register after ICE released them and the agency didn’t bother to follow up.

Judicial Watch has reported ICE’s many transgressions over the years, including how the agency released hundreds of violent illegal immigrants a few years ago over resource shortages. The offenders had been accused or convicted of serious felonies—including homicide, sexual assault and weapons violations—and ICE did not keep track of them after letting them go. A few years ago ICE came under fire for freeing an illegal immigrant felon who killed a Virginia nun and helping another undocumented alien escape justice for robbing an elderly man in Colorado.