Virginia State Police have eliminated the Virginia Tech Duck Pond from the list of places to hunt for evidence related to the April 16 shootings, spokeswoman Corinne Geller said Friday afternoon.

Using a grid pattern, the diving crews spent three days wading through the pond's mud and muck this week. They used metal detectors and their hands to search the entire pond, including the two smaller ponds adjacent to the lower pond.

Investigators won't say what they were looking for, although published reports alluded to a missing hard drive from shooter Seung-Hui Cho's computer.

"They were looking for anything that could have been of value or importance to the investigation," Geller said.

She said that did not mean anything in particular and that investigators were following up on all leads. Witnesses had told police they saw Cho at the pond between 8:10 and 8:20 a.m. on April 16.

Police and a separate team of divers scoured the pond and the surrounding area shortly after the shootings. Those searches also turned up nothing.

The second search was part of "hundreds and hundreds of pieces of evidence and leads," that police still are following, Geller said.

She could not say where police would turn their attention next, nor would she give a timeline to the investigation.

"When it comes to an investigation, you can't give a time, and we owe it to the families of those who were killed and those were injured and survived to make sure this investigation is done as timely and properly as possible," Geller said.

The investigation also meant teams from the Virginia Department of Game and Inland Fisheries, as well as Tech's fisheries department, had to help move wildlife to sections of the pond that were still underwater.

Now that the pond is back in Tech's hands, crews will assess the area for repairs, spokesman Mark Owczarski said.

Workers will fix the spillway between the upper and lower pond and look at the dam and the retaining walls to see if they need repairs. They will also clean the pond.

Just how long that might take is unknown, Owczarski said, because it depends on what else might be wrong.