DUNKARD TOWNSHIP, Pa. -- There is still no sign of a Greene County 12-year-old girl who went missing on her all-terrain vehicle.

Channel 11 has learned that the FBI is now involved in the case of missing Gabrielle Bechen.

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SLIDESHOW: Photos From Search

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She has been missing from her home in Dunkard Township since early Tuesday morning.

Bechen's parents called police when the girl did not return from riding her ATV.

The National Center for Missing and Exploited Children is also involved.

So far, there is no trace of Gabrielle or her ATV.

On Thursday morning, police continued their search of a three-mile area bordering West Virginia on foot, with dogs, ATVs and a helicopter.

Rescue workers from neighboring West Virginia, Maryland, Virginia and Delaware have joined in the search.

Police said Gabrielle was wearing tan shorts, a dark shirt and a black helmet the day she went missing.

If you have any information please call State Police.

Stay with Channel 11 News and refresh this page for continuing coverage on this story.