It's up to sex offenders to let law enforcement know where they are living and if they move, but not all offenders are following the honor system.
The law requires that sex offenders do not live close to parks or schools, but that's not stopping them.
A violent sex offender, Kelvin Calhoun, told police he was living in East Memphis, at an address listed on the online sex offender database.
But Calhoun was actually living in an apartment in Frayser, across the street from an elementary and high school.
"When they have been convicted, we expect they are going to be on the sex offender registry. Again, we cannot rely on that," said Virginia Stallworth, who is with the Memphis Child Advocacy Center
A sex offender must let law enforcement know they've moved within 48 hours. The information is then passed on to the Tennessee Bureau of Investigation.
It's not required local law enforcement agencies check in with the offender if they are not on probation or parole.
Shelby County Sheriff's Office and Memphis Police said they do, but wouldn't tell us how frequently.
"It's not as reliable, because the sex offender is able to slip under the radar, and not tell anyone if he is moving or anything," said parent Jen Steinmetz.
Shelby County deputies said sex offenders follow the rules for "the most part," but it's "hard to know who is not."
The Memphis Child Advocacy Center offers classes to the public to help detect child abuse and what to do if you think a sex offender is living close to you. The classes are $10.