Two men have brought what is believed to be the first legal challenges of Nebraska's sex offender registry law.
The Nebraska Supreme Court is to hear arguments in the cases on June 4th.
One challenge was brought by Gerald Welvaert Junior, who was convicted in 1996 of first-degree sexual assault in Sarpy County.
The other was brought by Terle Slansky of Kearney, who was convicted of rape and attempted rape in Kansas in 1985.
All states have such sex-offender registry laws, which require offenders to keep police informed of their addresses.
The court challenges say the law and the State Patrol's method of categorizing offenders is based on guess and conjecture.
They also say the registry denies sex offenders due process and adds punishment without a jury trial, among other things