Portsmouth's WAVY-TV broadcast video of investigators working under a blue tarp on a portion of Vick's wooded property in southeastern Virginia. They were sifting dirt collected in white buckets and clearing brush. Some wore T-shirts with the wording "POLICE."
The property includes a metal gate at the entrance of the large white house and a fence around the perimeter, which obscured the work of investigators. Fifteen vehicles were on the property, including a rental truck and a Virginia State Police evidence collections truck.
The U.S. attorney's office, contacted Friday by The Associated Press, would neither confirm or deny the search or an investigation. Surry County officials could not immediately be reached for comment.
Corinne Geller, a spokesman for the Virginia State Police, said state authorities were working with federal investigators in an "assistance capacity."
Vick has said he rarely visited the property. No charges have been filed.
During an April 25 drug raid at the property, authorities seized 66 dogs, including 55 pit bulls, and equipment commonly used in dogfighting. About half the dogs were tethered to car axles with heavy chains that allowed the dogs to get close to each other, but not to have contact, an arrangement typical for fighting dogs, according to the search warrant affidavit.
Investigators seized a "rape stand," used to hold dogs in place for mating; an electric treadmill modified for dogs; a pry bar used to open the clamped mouths of dogs; and a bloodied piece of carpeting.
Later, after an informant suggested authorities could find as many as 30 dogs buried on the property, including seven buried only days before the initial raid. Surry County officials secured a search warrant, but never acted on it because prosecutor Gerald G. Poindexter said he had concerns with the document.
On June 7, the day that warrant expired, federal officials executed their own with the help of state police investigators.
Poindexter publicly questioned the federal government's interest in a dogfighting case. He suggested that Vick's celebrity was the draw, and raised race as a possible motivation as well.
Poindexter and Vick are black, as is Sheriff Harold Brown.
Vick has said he had no idea the property may have been used in a criminal enterprise and blamed family members for taking advantage of his generosity. He also put the house up for sale and reportedly sold it quickly.