Officials in several states-- California, Georgia, Idaho, Michigan, Minnesota, Oregon and Wisconsin-- say sex offenders are not checking in with law enforcement. And many overworked local police departments are not following up.
All 50 states have laws that allow them to create databases of registered sex offenders and make their names and addresses available to the public.
Later this year, the U.S. Supreme Court is expected to rule on two cases that could change how states implement sex offender registries.
The high court is reviewing a Connecticut law denying sex offenders a right to a hearing before information about them is publicized. It also is reviewing a lower court ruling that it is unfair to list people on sex offender registries who completed their prison sentences before the law was enacted.
But neither case will address the basic problem with sex offender registries: states' inability to track felons. And no one knows how many missing sex offenders have committed more crimes. Nationally, 52 percent of rapists are arrested for new crimes within three years of leaving prison, according to the U.S. Bureau of Justice Statistics.
States require sex offenders to register, but some give false addresses, move without informing authorities, or evade registration altogether. The burden of keeping the accurate registries falls on local police departments that must launch investigations into felons' whereabouts.
"It's very time consuming," said Charlotte Marshall, sex offender registration analyst for the Michigan State Police. "We need more law enforcement funding. That's probably what the answer is."
Michigan has lost track of 1,313 of its 31,045 registered sex offenders, Marshall said.
Other states also cannot account for large percentages of registered sex offenders. In California, 44 percent of 76,350 registered offenders are missing. Wisconsin has lost track of 29 percent of its 9,900 sex offenders. More than 20 percent of the nearly 11,000 sex offenders who are required to register with the state of Minnesota can't be found.
Likewise, significant numbers of offenders are missing in Oregon (15 percent), Washington (10 percent), Idaho (9 percent) and Georgia (3 percent).
The answer to noncompliance could be more consistent prosecution for failure to register, said Dawn Peck, operations officer for the Idaho State Police's bureau of criminal identification.
Record-keeping problems sometimes arise when offenders relocate to other jurisdictions. Idaho's Peck works directly with other states' registries to track offenders' cross-border moves.
States are also working together to make sure felons are registered. Thirty-nine states have enacted the Interstate Compact on Adult Offender Supervision, which sets up uniform guidelines for how states send and receive information on offenders.
Despite such efforts to track offenders' whereabouts, some believe sex offender databases nationwide have fallen short of their promise.
Laura Ahearn, director of Parents For Megan's Law, a national victims' rights group, said "The problem starts with sex offenders registering themselves. If the states were being given the funding they needed to ensure these registries were up to date, it would involve longer supervision of ex-offenders. Then registration would be done by somebody in government, not necessarily by the offender."
