A 12-year-old Albuquerque girl says she was taken from her home and assaulted by a registered sex offender living nearby, but officials say that's no reason to doubt the system of registering offenders online.

"It enables the public to have the information they need," Bernalillo County Sheriff's Department Detective Amy Dudewicz said. "And this way, local law enforcement is doing something. We can monitor them (sex offenders) and know where they are."

Troy Herrera, 46, was arrested on July 11 and charged with kidnapping. He is being held in lieu of $100,000 cash-only bail.

In May, according to a Metro Court criminal complaint, he dragged a 12-year-old girl from her grandmother's home, where she was doing homework, into his apartment next door.

The girl told a social worker with the state Children, Youth and Families Department about the incident, who passed the information to authorities.

Herrera has been registered as a sex offender since 1992, when he was convicted of second-degree sexual assault in Freemont, Wyo.

Dudewicz said Herrera is required to check in annually with authorities. She said detectives work with probation officers to keep tabs on sex offenders.

Registered sex offenders are interviewed by the county's behavioral sciences unit, which produces a risk assessment on each individual. Dudewicz said Herrera was deemed a "low-to-medium" danger to others.

Though numbers weren't available, Dudewicz said there have been previous cases of registered sex offenders assaulting Albuquerque children.

The system, though, can still be effective, Dudewicz said.

Sex-offender public registry Web sites contain names, addresses and photos of registered offenders.

"It would be good for people to have the Web site and know what these people look like," Dudewicz said.

The Sheriff's Department has established a Sex Offender Registration and Tracking Unit, charged with notifying schools and day care providers when sex offenders are residing in their area. Anyone interested in helping to track sex offenders can call the unit at 841-9551.