EDMOND, Okla. -- A convicted sex offender who molested his niece when she was 7 years old moved in next door to his victim nearly a dozen years after he was sent to prison for the crime.

Outraged, the 21-year-old Oklahoma woman called lawmakers, the police and advocacy groups to plead with them to take action. Danyelle Dyer soon discovered that what Harold Dwayne English did in June is perfectly legal in the state -- as well as in 44 others that don't specifically bar sex offenders from living near their victims, according to the National Conference of State Legislatures.

"I don't like feel like I can come home," Dyer told CBS affiliate KWTV in June. "This is my safe zone and it's not really my safe zone any more."

"He's right there," she explained. "And not only does it scare me for my well being now, but it brings back a lot of things that happened in the past.

Dyer told KWTV that she now hopes to become a role model for other victims of sexual assault by bringing change to the state of Oklahoma.

Advocacy groups say the Oklahoma case appears to be among the first in the U.S. where a sex offender has exploited the loophole, which helps explain why dozens of other states have unknowingly allowed it to exist.

"This is something that I would dare say was never envisioned would happen," said Richard Barajas, a retired Texas judge and executive director of the nonprofit National Organization for Victim Assistance. "In all the years that I've been involved with the criminal justice system, I've never seen a case like this."

Alabama, Arkansas, Indiana, Tennessee and West Virginia have laws dictating how far away sex offenders must stay from their victims -- 1,000 feet in Tennessee, for example, and 2,000 feet in Arkansas. Other states haven't addressed the issue, though like Oklahoma they have laws prohibiting sex offenders from living within a certain distance of a church, school, day care, park or other facility where children are present.

"You assume it can't happen and then realize there is no provision preventing it from happening," said one Oklahoma prosecutor, Rogers County District Attorney Matt Ballard, whose agency is responsible for keeping tabs on sex offenders in his area. "To have even the possibility of an offender living next to the victim is extremely troubling."

Arkansas passed its provision in 2007. State Sen. Jeremy Hutchinson, a former prosecutor, said lawmakers drafted the provision out of "common sense," not as a response to a situation like Dyer's.

Read more at CBSNews.com.