After Jacob Wetterling was abducted in 1989, a pastor named Thomas Gillespie of the St. Joseph Parish offered support and comfort to the Wetterling family. He invited them to dinner, opened the church for a community prayer service and presented them with hot cross buns at Easter. What the Wetterlings did not know at the time was that Gillespie was a sex offender who admitted molesting a boy in the 1970s and was finally removed from the ministry in 1996.

"He showed up on their list of perpetrators years later," Jacob's mother, Patty Wetterling, said of the pastor who inserted himself into their lives. "I felt so betrayed. How could he do that? I mean, he knew our pain. He knew our journey. ... He'd bring kids out to swim at the racquetball club. I think he had his pilot's license. He'd take kids out flying. He seemed like this genuinely nice person who was doing good things for kids. And it was so sad to know some of these kids were being victimized."

At the time of the Wetterling abduction, residents of the small city of St. Joseph, Minn., near St. Cloud, had no idea how many sex offenders lived in the area. Children had free reign and doors were left unlocked. Yet just six miles away, St. John's Abbey had been home at various times to more than a dozen clerics who were sex offenders. Other offenders lived in the immediate area as well, including gropers, rapists and perpetrators of incest, some of whom would be swept up in the investigation. When Danny Heinrich confessed recently to molesting and murdering Jacob, he also admitted to sexually assaulting another boy nine months earlier, a crime for which he was investigated but never prosecuted.

"I was so naively innocent," Wetterling said. "I was involved in the school and started the PTA and I was active but I didn't know about victimization of children." The experience convinced her that if the police were more aware of the presence of sex offenders — through a centralized list or registry — they would be better able to protect the children living in their jurisdictions, a notion that is now in dispute.

The Wetterling abduction led, in 1994, to the first national mandate that states establish registries of convicted sex offenders. As of 2013, those state lists contained more than 700,000 names, according to one analysis, greater than the population of Seattle, with more than 500,000 of them listed publicly. And the numbers keep growing as new types of offenders are included. Many are registered for serious crimes, but others may be listed for offenses like public urination, sexting and conducting so-called "Romeo and Juliet" relationships between teenagers.

Alissa Ackerman

Many in the field have come to believe that sex-offender registries, as they are currently implemented, do more harm than good. They do not address the fact that most sex offenders are family members, friends or acquaintances of the victim, not strangers. Beyond that, inclusion in a sex-offender registry makes it all but impossible for a person to rent an apartment or land a job or live a stable life. Existing at the margins, or beyond the margins, can cause stress and lead to new offenses. Registries, community notification policies and geographical living restrictions can drive offenders underground where they are harder to help and keep track of. They can push offenders into poor, chaotic neighborhoods, where the most vulnerable children reside. Most damning, studies show that registries tend not to decrease sex crime recidivism — which, on average, is lower than many believe, around 15 percent after five years, according to a preponderance of research cited in a 2014 report from the Washington, D.C.-based National Criminal Justice Association.

"For the most part, sex-offender registration and notification are not effective," said Alissa Ackerman, a researcher and criminal justice professor at the University of Washington. "They really do nothing to prevent sex crimes from occurring. They destabilize the people who are on registries and what we know from the criminological literature is that when people have stable housing, stable jobs and stable interpersonal relationships, they're less likely to reoffend. And sex-offender registries make it so they don't have (those things). In many ways, we could actually be making the problem worse by mandating people to the registries."

Even Wetterling has come to believe the lists have gone too far and has been publicly urging caution. "What we really want is no more victims," she said. "Don't do it again. So, how can we get there? Locking them up forever, labeling them, and not allowing them community support doesn't work. I've turned 180 (degrees) from where I was."

After the 1994 passage of the Jacob Wetterling Crimes Against Children and Sexually Violent Offender Registration Act, which required that states track sex offenders, came Megan's Law. That 1996 law, named after a girl who was raped and murdered by a convicted sex offender in New Jersey, went a step further by requiring the authorities to release information about offenders to the public. Together, the laws established a broad national framework for offender registration and notification.

The evidence is mixed on whether registries have had a positive or negative effect on safety. Ackerman and her co-researchers recently completed a study that looked at whether Megan's Law has led to decreases in rape. "We found it didn't do anything," she said. "There were no effects at all."

While a few studies show a decrease in recidivism with registration and notification and a deterrent effect (one found a deterrent effect but, at the same time, an increase in recidivism), there are as many or more studies that show the opposite. "If you look at the majority of studies, there are a lot of collateral consequences that outweigh the small deterrent effect it may have for some people," Ackerman said.

In its 2014 analysis of sex-offender management policies, the National Criminal Justice Association concluded that more, and better, research is needed. The association noted that in terms of sex-offender registration and notification, the research "has exhibited mixed results on sex-offender crime rates and recidivism. Studies have not adequately controlled for outside factors that might serve as an alternative explanation for the observed study outcomes."

One 2006 study cited in the analysis measured the rates of reported rape in 10 states before and after sex-offender registration and notification laws went into effect. It found that rates declined in three states, stayed the same in six states, and increased in one state. There was "no systemic influence" of sex-offender registries on the rate of reported rape, the authors concluded.

Richard Tewksbury

But public support for registration remains strong, the report said. "In the research community, yes, it's very widely accepted that the literature is almost unanimous in (saying there is) exceptionally little or no positive effect," said Richard Tewksbury, a professor of criminal justice at the University of Louisville.

It's difficult to determine cause and effect in sex-offender programs, he said. "I mean, the most effective way to prevent recidivism is just to kill every known sex offender. That'll be sufficient and you know it'll work," Tewksbury said. "But short of that, you just can't know what led to it. Sorting out the real effect of any kind of intervention, especially that's preventive in nature, is exceedingly difficult if not impossible."

In addition, states have different rules for inclusion in registries. Those rules are implemented unevenly, creating disparities in punishment and unreliable information. Registries include misspellings, failures to list offense types, even dead people. "So, because of the number of people being added and number of offenses people can now be on the registry for, there's not enough manpower to input the data as necessary so there are a lot of mistakes, a lot of typos, a lot of missing information," Ackerman said. "The registry really is sort of ineffective at doing what it's intended to do."

Accuracy varies from state to state. The National Criminal Justice Association report, found 90 percent accuracy in Nebraska but only 56.5 percent accuracy in Oklahoma. A random sampling of records in the New York registry found that 37 percent of the records were inaccurate, "including 27 percent that did not match driver's license information and 2.5 percent that had wrong addresses." In Vermont in 2010, "75 percent of the records were found to have critical or significant errors."

The Adam Walsh Child Protection and Safety Act of 2006, named for a boy who was kidnapped and beheaded in Florida, expanded the pool of offenders who could be included in the registries and was supposed to standardize the listing criteria and implementation. But the states remain inconsistent. As of 2014, the Justice Department reported that only 17 states, three territories, and 63 Native American tribes had "substantially implemented" the registry requirements of the Adam Walsh Act, according to the National Conference of State Legislatures. Ackerman has been compiling data on who is included in the registries and for which offenses, no easy task given the incomplete or inaccurate listings. She has finished her analysis, but has not yet released the report.

Of the more than 500,000 publicly listed sex offenders in 2013, about 480,000 had a crime associated with a name in the registries. Of those, about 14 percent were included for rape and 4 percent for pornography. Just under 60 percent of the victims of the listed crimes were minors. About 13 percent of the crimes were noted to be "aggravated," usually connoting violence. The offenders on the lists were 98 percent male and 60 percent white.

"The vast majority of people who are committing sex crimes are not on the registry," Ackerman said. "So, we're looking to strangers, we're looking to people in the community, when really abuse is happening in our homes and our schools and our day cares. We're not looking in the right place. It sort of diverts our attention from the everyday."

It's unclear how many offenders listed in the state registries were juveniles at the time of their offenses. But the inclusion of teenagers, who have the greatest chance of turning their lives around, has soured some on the very idea of registries.

"We've criminalized them and, yeah, we have high school kids convicted," Tewksbury said, "and they're now on the registry for 20 years or life, and that's simply something they're going to have to deal with," Tewksbury said. "They're not all the serious leap-from-behind-the-dumpster (rapes) but they're also not necessarily peeing-in-the-park folks. We're talking about the full range of sex offenses including a lot of noncontact offenses — child porn, the internet luring kinds of ideas. Even sexting. ... If I am a 15-year-old boy, if I take a picture of my genitals and sext it to whomever, I've just created child porn and distributed it. That sounds horrible, and they may want to lock me up forever. 'But hey, I just thought it was funny.'"

Offender registries today are much larger and more punitive than anticipated in 1994. "These laws were originally designed for dangerous repeat offenders who had harmed young kids they didn't know," Ackerman said. "But what we're finding is that really only a small percentage of people that are on the registries are high risk. ... The vast majority are not high risk people so it calls into question whether or not they should be on the registry in the first place."