On the afternoon of Jhon Sanchez’s 18th birthday, three parole officers showed up at his home in West New York, NJ. Sanchez was in his slippers and shorts, and when his mother asked if she could grab her son something else to wear, an officer assured her that Sanchez would be gone only for a little while.

That was five years ago.

Sanchez is behind bars, but he is not in a regular prison. He is considered a resident, one who is detained involuntarily and indefinitely at the Special Treatment Unit for sexually violent predators, commonly known as Avenel. He is among 428 people who have been “civilly committed” at the facility, all of them living in limbo.

Although they have already served prison sentences for their crimes, these inmates have been classified by state psychologists as unfit to return to society.

The civil commitment of “sexually violent predators” is intended to protect the public: In theory, offenders are offered extensive therapy to help them learn to control sexual impulses. But an analysis by The Marshall Project shows most people who enter civil commitment programs nationwide are detained for years and, in most cases, have a slim chance of being released. About 15 percent of the 579 people who have been committed at Avenel since the program’s inception in 1999 have been discharged to the community after treatment.

The state estimates there are 15 patients at Avenel who were never convicted as an adult but were sent to Avenel, indefinitely, once they completed their sentences. Public defenders and attorneys for the residents put the number at 30.

Critics cite such statistics to argue that civil commitment has become a gray, arbitrary area of the law. “We’re effectively handing out life sentences to juveniles under the auspices of civil commitment,” said David Prescott, former president of the Association for the Treatment of Sex Abusers.

In recent months, federal judges in two states have ruled the application of civil commitment laws unconstitutional. In June, a judge said Minnesota’s “punitive system” lacks the “safeguards of the criminal justice system.” Then in September, a Missouri judge banned the lifetime detention of individuals who have served their sentences and “who no longer pose a danger to the public, no matter how heinous their past conduct.” In October, two British high court judges blocked the extradition of Roger Alan Giese, wanted in California for charges of sexually abusing a young man; the possibility that Giese would be civilly committed posed a “flagrant denial” of his rights under the European Convention of Human Rights.

Nearly 5,400 people are currently civilly committed in sexually violent predator programs in 20 states and by the federal Bureau of Prisons. Thirteen states allow this practice for people who committed their crimes as juveniles, like Sanchez. Despite having no adult convictions, they are being held years into adulthood, which, according to some psychologists, does more harm than good to the development of their minds.

After five years, Sanchez is on the second treatment phase of five. Psychologists hired by the state assess him every six months to determine whether he is fit to leave. According to a recent treatment review report, Sanchez remains “highly likely to sexually reoffend if not confined to a secure facility.”