The story of Curtis Mongold, who was convicted in Douglas County for sexually abusing a girl and who served three years in prison, is disturbing.

As part of his sentencing, Mongold received a lifetime requirement to register as a sex offender. He told Kansas authorities he was moving to California in 2001, but there is no record of him in California, according to the National Sex Offender Public Website, which collects registry information from all 50 states.

Of the 4,500 registered sex offenders in Kansas, only 8 percent are currently not complying with the registration requirements, which include verifying home addresses four times a year. In the corrections community, that’s considered a good record.

But a Journal-World investigation identified 161 registered sex offenders like Mongold who have moved out of Kansas since 2006 but do not show up on offender registries in the states to which they reportedly moved.

The Kansas Bureau of Investigation sends letters to states that offenders move to, but after that it’s somebody else’s responsibility. There could be cases where an offender moves to one state, then to another, but that information isn’t necessarily communicated among states, KBI officials say.

That worries Laura Ahearn, executive director of Parents for Megan’s Law and the Crime Victims Center, a nonprofit advocate for accountability in sex offender registries nationwide. Different laws in different states make keeping track of sex offenders a complicated endeavor, Ahearn said. In some cases, an offender in one state may not be required to register in another state.

That’s the problem. Sex offenders shouldn’t be one state’s concern and not another’s. The offenders are a concern for every state and should be followed by all as long as they are required to be on a registry.

Despite the issues identified by the Journal-World investigation, Kansas has taken steps to improve its sex offender registry, but numbers pointed out in the J-W story show that far better national tracking systems are needed.

A state law that went into effect July 1 strengthened Kansas’ offender registry, increasing penalties for offenders who fail to register and reducing from 10 to three days the length of time offenders have to notify authorities of an address change. The updates made Kansas just the 10th state in the country to comply with the 2006 federal Sex Offender Registration and Notification Act, known as SORNA.

SORNA gives the U.S. Marshals Service authority to investigate sex offenders who move out of state but fail to register in their new state. The U.S. Marshals’ office now relies on tips from the public and law enforcement about which offenders are not in compliance across state lines.

For the protection of all U.S. residents, all 50 states must be part of the SORNA program. Communities should not be left in the dark when dangerous offenders move in from another state.