Investigators who searched campsites where Elizabeth Smart said she was held captive for two months found several knives, one at each of the hidden camps.
Police are trying to determine which of the knives Brian David Mitchell allegedly used to abduct the girl last June, a source close to the investigation told the Associated Press Friday.
The source, who spoke on condition of anonymity, said Mitchell kept a knife at each of several hidden camps, moving from camp to camp to avoid thousands of volunteers who searched the Wasatch foothills after her abduction.
The knives were recovered after the girl pointed out the camps from a helicopter last weekend.
The network of camps was found scattered on the upper slopes of west-facing Dry Creek Canyon, about 3.5 miles from the Smart home, where Elizabeth had a view of the city.
At one of the camps investigators found a hole dug in the ground and covered with boards where they believe Elizabeth and her captors were shielded from helicopters equipped with infrared sensors, which can detect body heat, the official said.
Elizabeth also was held for a time by a cable tethered to a tree.
Mitchell has been accused of taking Elizabeth at knifepoint from her bedroom by slicing a window screen at the home. Both Mitchell and his wife, Wanda Barzee, face multiple counts, including aggravated kidnapping, aggravated sexual assault and aggravated burglary. They are being held in the Salt Lake County Jail on $10 million each.