Federal agents investigating possible dogfighting searched property owned by Michael Vick on Friday using shovels and heavy equipment.

A backhoe-front loader was brought in and used to scoop up sections of a cleared wooded area in the rear of the property. The material was dumped into ice-filled coolers and loaded into a rental truck, which left the property. Some investigators wore T-shirts with the words "Federal Agent USDA."

Fifteen vehicles were on the property, including a Virginia State Police evidence collections truck.

Corinne Geller, a spokesman for the Virginia State Police, said state authorities were working with federal investigators in an "assistance capacity."

The U.S. attorney's office, contacted Friday by The Associated Press, would neither confirm nor deny the search or an investigation. Surry County officials could not immediately be reached for comment.

Vick, the Atlanta Falcons quarterback, has said he rarely visited the property. No charges have been filed. Federal and state police investigators also searched the property on June 7.